A B C D E F G H I K L M N O P Q R S T U V W Y Z
ABSTRACT OF TITLE
A compilation of abstracts of deeds, trust deeds, and other pertinent data which affects the title to a piece of real property, all bound together in chronological order, constitutes an abstract of title. It is a form of title evidence made for the purpose of title examination.
ABUT
To reach or adjoin. In old law the sides of a property adjoined, whereas the ends were said to abut.
ABUTTALS
Boundaries or buttings of land; adjoiners.
ACCESSORIES TO CORNERS
Physical objects adjacent to corners that have a measured or known relationship to the corner and can be used to identify original corners; these include memorials, bearing trees, mounds, pits, rocks, fences, banks. Accessories are often considered as part of a corner monument itself rather than as “aiding in a secondary way.”
ACCRETION
Increase by external addition; enlargement; the act of growing to a thing. Where, from natural causes, land forms by imperceptible degrees upon the bank of a river, stream, lake, or tidewater, either by accumulation of material or recession of water, the process is called accretion and the end result is called accretions. The process of land formation is also called alluvion and the land itself is called alluvium.
ACCURACY
Degree of conformity with a standard or accepted value. Accuracy relates to the quality of a result, and is distinguished from precision which relates to the quality of the operation by which the result is obtained.
ADDRESS [GIS]
GIS geocoding software that can identify street addresses (such as those matching compiled in the US Census Bureau?s TIGER data) by conversion from grid coordinates.
ADJACENT
“To be near,” “close or contiguous,” “in the neighborhood or vicinity of but not necessarily touching,” or “adjoining or continuous to” are the common meanings of adjacent. More often used to mean adjoiner; and, if so, adjoiner should be used in preference to adjacent.
ADJOINER
Adjoin means to be in contact with’ hence the adjoiner is the land in contact with the instant property. When speaking, it is often used to mean the written deed of the adjoiner.
ADVERSE POSSESSION
A method of acquisition of title by possession for a statutory period under certain conditions.
ALIQUOT
A part of a distance that divides the distance without a remainder.
ALLUVION
Where, from natural causes land forms by imperceptible degrees upon the bank of a body of water, navigable or not navigable, either by accumulation of material or by the recession of water, such land, called alluvium, belongs to the owner of the bank subject to any existing right of way over the bank. The process of land formation is called alluvion or accretion.
ALMANAC[GPS]
Data sent from the GPS Satellites containing a summary of the orbital parameters of all GPS satellites. This data can be used to find other GPS satellites
ALONG
“Along a line” means on and in the direction of the line; it implies motion. “Along the road” means along the center line or thread of the road unless qualified as, for example, “Along the east side line of the road.” “Along a line” may be changing in direction by curves or angles. Avoid “with a line,” “by a line,” or “on a line” where “along a line” is meant. The term “along” may mean “on”; thus “along the shore” means “on” the shore and includes the shore (Church v. Meeker, 34 Conn 421). “With a line,” meaning “along a line,” is commonly used in the eastern United States.
ALTIMETER
An instrument for measuring elevation or height above a reference datum. An instrument which determines height by measuring the weight of air above it is called a barometric, aneroid, pressure, or sensitive altimeter.
ALTITUDE
Angular distance above the horizon; the arc of a vertical circle between the horizon and any point on the celestial sphere. Measured in units of degrees, minutes, seconds.
ALTITUDE, APPARENT
The observed vertical angle of a celestial object corrected for instrumental errors, personal errors, and inaccuracies in the reference level, but not for refraction of parallax.
AMBIGUITY, LATENT
An uncertainty which does not appear upon the face of an instrument, but arises from evidence aliunde, that is, one which is not involved in the words themselves, but arises from outside matters; thus, a conveyance to “John Smith, living on Fifth Avenue,” when it appears that there are two or more John Smiths so living, contains a latent ambiguity. Opposed to patent ambiguity.
ANALYSIS[GIS]
The process of identifying a question or issue to be addressed, modeling the issue, investigating model results, interpreting the results and possibly making recommendations
ANNOTATION[GIS]
Descriptive text used to label features on or around a map. Information stored for annotation includes text string, a position at which it can be displayed and display characteristics.
ANTISPOOFING (AS)[GPS]
Encryption of the P-Code to render spoofing ineffective. Spoofing is creating false P-code transmission. The encrypted code is known as Y-code. AS began in 1994. Commercial receivers do not use the P-code
APPARENT SOLAR DAY
The interval of time between two successive lower transits of the Sun’s center over the same meridian.
APPARENT TIME
The Hour Angle of the Apparent Sun, with respect to the lower limb of some meridian.
APPROXIMATE
“Approximately,” “a little more than,” “not quite,” “not more than” are all terms of safety and precaution. Approximate of ten denotes uncertainty of dimensions to a greater degree than “more or less” and to a lesser degree than “about.” Near to correctness; nearly exact; not perfectly accurate. Reasonable knowledge of dimensions is indicated by the word approximate.
APPURTENANCES
A word employed in deeds, leases, etc., for the purpose of including any easements or other rights used or enjoyed with the real property, which are considered to be so much a part of the property that they automatically pass to the grantee under the deed conveying the real property. From appertain; to belong to.
ARC[GIS]
An arc is a line entity, used in topology. See link.
ASTRONOMICAL TRIANGLE
The triangle on the celestial sphere formed by arcs of great circles connecting the celestial pole, the zenith and a celestial body. The angles of the astronomical triangles are: at the pole, the hour angle; at the celestial body, the parallactic angle; at the zenith, the azimuth angle. The sides are: pole to zenith, the co-latitude; zenith to celestial body, the zenith distance. Also called the PZS triangle.
ATOMIC CLOCK[GPS]
A clock regulated by the resonance frequency of atoms or molecules. GPS Satellites us Cesium, Hydrogen and Rubidium Atomic Clocks
ATTRIBUTE[GIS]
This is a non-graphical descriptor of a geographic feature or entity; it can be qualitative or quantitative – such as numerical codes tied to qualitative descriptors, e.g., the number 8 representing A commercial development on a land-use layer
AVULSION
The sudden and perceptible separation of land by violent action of water. A stream suddenly adopting a new channel and dividing a parcel into two parcels. Title usually follows the old channel; however, the statute of limitations may specify how soon a person must reclaim the portion cut off. In California it is one year after the necessity to act.
AZIMUTH, ASTRONOMIC
At the point of observation, the angle measured between the vertical plane through the celestial pole to the vertical plane through the observed object. A horizontal angle determined directly from the observation on the sun, moon or stars.
AZIMUTH, GEODETIC
At the point of observation, the angle measured between the true meridian of the spheroid representing the earth and a plane normal to the spheroid through the observed object. A horizontal angle determined from astronomic observations with corrections to the astronomic azimuth for the difference between geodetic and astronomic longitude; or by correcting State Plane Grid azimuth by the theta angle in the Lambert Conic Project system.
AZIMUTH, MAGNETIC
At the point of observation, the angle between the vertical plane through the observed object and the vertical plane in which a freely suspended, symmetrically magnetized needle, influenced by no transient artificial magnetic disturbance, will come to rest.
BALANCING A SURVEY, COMPASS RULE
Corrections corresponding to the closing errors in latitude and departure are distributed according to the porportion-length of line to total length of traverse. The compass rule is used when it is assumed that the closing errors are as much a result of errors in observed angles as of errors in measured distances.
BALANCING A SURVEY, TRANSIT RULE
Corrections corresponding to the closing errors in latitude and departure are distributed according to the proportion–latitude and departure of each line of the traverse to the arithmetical sums of the latitudes and departures of the entire traverse. The transit rule is used when it is assumed that the closing errors are caused less by the errors in the observed angles than by the errors in the measured distances.
BASE STATION[GPS]
A base station is a GPS receiver at an accurately-known fixed location which is used to derive correction information for nearby portable GPS receivers. This correction data allows propagation and other effects to be corrected out of the position data obtained by the mobile stations, which gives greatly increased location precision and accuracy over the results obtained by uncorrected GPS receivers
BASELINE[GPS]
A line described by two stations from which GPS observations have been made simultaneously.
BEARING
The direction of one point or object, with respect to another, where the direction of the line is expressed by the acute angle with respect to a reference meridian. The reference direction can be North or South and the meridian may be assumed, grid, magnetic, astronomic, or geodetic. Typical bearings are N 60°10’E, S 3l°17’W, N 17°22’W.
BEARING TREE
A tree marked or called for to witness the position of a corner (usually a section corner). It is usually blazed with the corner number inscribed.
BIAS[GPS]
A systematic error. Biases affect all GPS measurements and results. Modeling is one method used to eliminate or limit the effect of biases
BLAZE
Blaze is a mark on a tree caused by cutting off the bark and a portion of the live wood, usually at breast height with a flat scar.
BLOCK I II,IIR & IIF SATELLITES[GPS]
Generation of GPS Satellites: Block I were considered experimental, and none are currently operational. Block II were the operational satellites and 27 have been launched.
BLUNDER
A mistake. Not an error. An error is a small residual error of measurement. A blunder is misreading (96 for 69 etc.).
BUFFER[GIS]
A specified zone around a entity which can be used to query a database.
BUREAU OF LAND MANAGEMENT
An agency of the United States Department of the Interior created by Executive Order effective July 16, 1946, superseding the General Land Office in the administration of the general land laws, with supervision of the subdivisional survey, and disposal of title to the public lands of the United States, and of the leasing, grants of right-of-way, and other surface uses thereof, including all rights incident to the extraction of minerals, coal, phosphates, potash, oil, and gas on the public lands; withdrawals for irrigation, dams, and reservoirs; and for grazing, and settlement rights of every description. A number of regional offices have been established to facilitate and expedite the administration of current activities. (The Chief Forester, United States Department of Agriculture, administers every type of timber use within the national forests, and special privileges therein, both where established by withdrawal from the public domain, and where acquired by purchase.)
BY
In a deed, “by a road” is construed as including the land to the center of the street, but “by the east side of a road” means “along the east side” and not “along the center line.” “To,” “on,” or “by” a stream means to the limits of the grantor’s land. By has many meanings and is usually used in deeds to mean “along,” “over,” or “through” as “by 5th Street.” It can mean “near,” “close,” “within reach,” or “toward” (east by north).
C/A CODE[GPS]
A binary code known as the Course Acquisition code (Also Civilian Access; Clear Access; Clear Acquisition) It is the standard Pseudorandom noise code generated by each satellite. It is modulated on the L1 carrier
CADASTRAL SURVEY
A survey relating to land boundaries and subdivisions, made to create units suitable for transfer or to define the limitations of title. Derived from “cadastre,” and meaning register of the real property of a political subdivision with details of area, ownership, and value. The term cadastral survey is now used to designated the surveys of the public lands of the United States, including retracement surveys for the identification and resurveys for the restoration of property lines; the term can also be applied properly to corresponding surveys outside the public lands, although such surveys are usually termed land surveys through preference.
CALL
A “call” within a deed is the designation of visible natural objects, monuments, course, distance, or other matter of description as limits of the boundaries. Locative calls are particular or specific calls exactly locating a point or line. Descriptive calls are general or directory calls which merely direct attention to the neighborhood in which the specific calls are to be found.
CARRIER FREQUENCY[GPS]
The frequency of the unmodulated signals broadcast by the satellites. L1 broadcast at 1575,42MHz and the L2 at 1227.60Mhz.
CARRIER PHASE[GPS]
The portion of the carrier wavelength measured. L1 has a wavelength of about 19cm and L2 about 24 cm.
CARRIER[GPS]
An electromagnetic wave that can be modulated to carry information.
CARTOGRAPHY[GIS]
The art and science of showing land cover and/or land use graphically, such as on a map.
CELESTIAL EQUATOR
The intersection of the celestial sphere and the extended plane of the earth’s equator.
CELESTIAL POLE
Either of the two points of intersection of the celestial sphere and the extended axis of the earth, labeled N or S to indicate whether the north celestial pole or the south celestial pole.
CELESTIAL SPHERE
An imaginary sphere of infinite radius, described about an assumed center, and upon which imagined positions of celestial bodies are projected along radii passing through the bodies. For observations on bodies within the limits of the solar system, the assumed center is the center of the earth. For bodies outside these limits the center of celestial sphere can be taken as coinciding with the point of observation.
CELL[GIS]
The basic rectangular element of a raster grid – it is called a pixel in digital images
CENTER OF SECTION
The point formed by lines connecting opposite quarter corners in a section of land. It is also called the center quarter corner.
CENTROID[GIS]
The centerpoint (or other identified point) of a polygon at which location attribute information for that polygon may be tagged. For example, for a polygon representing a specific neighbourhood, population, assessment, voting preferences, etc., all may be stored at the designated centroid coordinates or grid cell.
C-FACTOR
An empirical evaluation which expresses the vertical (elevation) measuring capability of a stereoscopic system; generally defined as the smallest contour interval which can be plotted to required accuracy. The C-factor is not a fixed constant. It varies over a considerable range, according to the conditions of the photogrammetric system and the preicision of use. The C-factor is often used to determine the flight height from which aerial photographs should be taken for photogrammetrically accomplishing topographic mapping, at the smallest contour interval accurately plottable from using a particular aerial camera and instrument system. The practicable flight height is the contour interval multiplied by the C-factor.
CHAIN
An instrument used to measure land which was 33 feet long with 50 links. Later chains were 66 feet long with 100 links. As a unit of measure, 1 chain equals 66 feet.
CHAIN OF TITLE
A chronological list of documents which comprise the record history of title of a specific parcel of real estate.
CHAIN[GIS]
Directional and non-intersecting arcs or strings having nodes at each end are called chains in topology
CIRCLE, GREAT
The line formed by the intersection of a sphere and a plane which passes through the center of the sphere.
CIRCLE, SMALL
The line formed by the intersection of a sphere and a plane which does not pass through the center of the sphere.
CIRCLE, VERTICAL
Any great circle of the celestial sphere passing through the zenith (and nadir). Also, a divided circle mounted on an instrument in such a manner that the plane of its graduated surface can be placed in a vertical plane.
As a great circle, a vertical circle is the line of intersection of a vertical plane with the celestial sphere.
As an instrument, a vertical circle may be an auxiliary attachment to a theodolite or transit, or it may be the major feature of an instrument intended primarily for use in measuring vertical angles in astronomical and geodetic work. In geodetic work, such an instrument is termed a vertical circle.
CLEAR TITLE
Good title; one free from encumbrances.
CLOCK OFFSET[GPS]
The difference between the same moments in time indicated by two clocks
CLOUD OF TITLE
A claim or encumbrance on a title to land that may or may not be valid.
CO-DECLINATION
Ninety degrees minus the declination. When the declination and latitude are of the same name, co-declination is the same as polar distance measured from the elevated pole.
CO-LATITUDE
The complement of the latitude, or 90? minus the latitude. Co-latitude forms one side, zenith to pole, of the astronomical triangle. It is the side opposite the celestial body.
COLOR OF TITLE
If a claim to a parcel of real property is based upon some written instrument, although a defective one, the person is said to have color of title. The title appears good but in reality it is not.
COMMON LAW
The body of judicial decisions developed in England and based upon immemorial usage. It is unwritten law as opposed to statute, or written, law. The English common law forms the foundation for the system of law in the United States.
COMMON REPORT
By reputation certain markers are commonly accepted by surveyors and others as being correct, even though they cannot positively be proved to be correct. As time progresses and the records of replacement of original property monuments are lost, surveyors become more and more dependent upon the acceptance of monuments whose history is lost in antiquity. If people accept a monument, and especially if numerous surveyors accept a monument, the monument is said to be the true marker by common report.
CONCAVE
The inside of a curve; toward the center of the circle.
CONSTELLATION[GPS]
The GPS Satellites. A full constellation consist of 24 satellites
CONTIGUOUS
Varies in meaning from in close proximity to near, though not in contact to, touching or bounded or traversed by.
CONTINUALLY OPERATING REFERENCE STATION (CORS)[GPS]
A system of base stations that continually collects GPS data from stable base Stations. These stations are now part of the adjustment of NAD83
CONTOUR INTERVAL
The difference in elevation between adjacent contours on a map.
CONVEYANCE
The term conveyance embraces every instrument in writing by which any estate or interest in real property is created, aliened, mortgaged, or encumbered, or by which the title to any real property may be affected, except wills.
CONVEYANCE, SEQUENCE
Sequence conveyances are those written deeds in which junior and senior titles exist between adjoining parcels.
CONVEYANCE, SIMULTANEOUS
Where several parcels of land are created simultaneously, by the same person or persons, and by the same instrument, all have equal standing and no part can be said to have prior rights or seniority over any other part. Such conveyances are said to be simultaneous conveyances.
CORNER
A point on a land boundary, at which two or more boundary lines meet. Not the same as monument, which refers to the physical evidence of the corner’s location on the ground.
CORNER, CLOSING
A corner (usually marked by a monument) indicates where the new line intersects a previously established land boundary. The point at which a section line closes (intersects) on a prior Rancho land grant, correction line, water boundary, etc. Closing corner monuments are not considered as fixed in position, but may be adjusted by a later surveyor to the line closed on. They are an exception to the rule that “wherever an original monument is set, its position is unalterable.”
CORNER, LOST (USPLS)
A previously established survey corner whose position cannot be recovered beyond reasonable doubt, either from traces of the original marks or from acceptable evidence or testimony that bears on the original position, and whose location can be restored only by reference to one or more interdependent corners.
CORNER, OBLITERATED (USPLS)
A corner at which there are no remaining traces of the monument or its accessories, but whose location has been perpetuated or may be recovered beyond reasonable doubt, by the acts and testimony of the interested landowners, competent surveyors, other qualified local authorities, witnesses, or by some acceptable record evidence. A position that depends upon the use of collateral evidence can be accepted only as duly supported, generally through proper relation of known corners, and by agreement with the fieldnotes regarding distances to natural objects, stream crossings, line trees, and off-line tree blazes, etc., or unquestionable testimony.
COURSE
1) (land surveying) The bearing of a line; also the bearing and length of a line. 2) (transit traverse) The azimuth and length of a line, considered together. 3) (navigation) The azimuth or bearing of a line along which a ship or aircraft is to travel or does travel, without change of direction; the line drawn on a chart or map as the intended track. The direction of a course is always measured in degrees from the true meridian, and the true course is always meant unless it is otherwise qualified; e.g., as a magnetic or compass course. 4) (geography) A route on the earth along which a river flows; the river itself.
COVENANT
A word used in deeds for the purpose of creating restrictions; imports an agreement on the part of the grantee to make, or to refrain from making, some specified use of the land conveyed.
CULMINATION
The position of a heavenly body when at highest apparent altitude (zenith). Known as upper culmination; also, for a heavenly body which is continually above the horizon, the position of lowest apparent altitude, known as lower culmination. Culmination occurs when the body transits the local meridian.
CYCLE SLIP[GPS]
A discontinuity of an integer number of cycles in the carrier phase observables. A cycle slip causes cycle ambiguity to change suddenly.
DATUM
Any position or element to which others are determined. In Latin, a thing given. If there are more than one reference datum, the plural is datums, not data; i.e., there have been several sea level datums used.
DATUM[GPS]
A reference surface used as a basis for positioning. World based datums use an ellipsoid model and a network or framework of fixed monuments
DECLINATION (astronomy)
The angle at the center of the celestial sphere between the radius passing through a celestial body and the plane of the celestial equator. Astronomic declination is measured by the arc of the hour circle between the celestial body and the equator; it is plus when the body is north of the equator, and minus when south of it. It corresponds to latitude on the earth, and with right ascension forms a pair of coordinates which define the position of a body on the celestial sphere.
DEDICATION
To dedicate means to appropriate and set apart land from one’s private property to some public use. The dedication may be either express or implied. It is express when there is an express manifestation on the part of the owner of his purpose to devote the land to a particular public use, such as the streets in platted subdivisions. It is implied when the owner’s acts and conduct manifest an intention to devote the land to the public use. To make the dedication complete, there must not only be an intention on part of the owner to set apart the land for the use and benefit of the public, but there must be an acceptance by the public.
DEEDS
Act; action, thing done. At law a deed is evidence in writing of an executed and delivered contract, usually for sale of land. As pertaining to land, its purpose is to define location and title to land. Several types exist. (1) Grant Deed. A grant deed conveys the fee title of the land described and owned by the grantee. If at a later date the grantor acquires a better title to the land conveyed, the grantee immediately acquires the better title without formal documents (after rights). In some states, by law, the grantor warrants the deed against acts of his own volition. (2) Quitclaim Deed. A quitclaim deed passes on to the grantee whatever title the grantor has at the time at which the transaction is consummated. It carries no after rights; i.e., if the grantor acquires a better title at a later date, it is not passed on to the grantee. The deed carries no warranties on the part of the grantor. (3) Agreement Deed. An agreement deed is an agreement between owners to fix a disputed boundary line. (4) Warranty Deed. A warranty deed conveys fee title to the land described to the grantee and in addition guarantees the grantor to make good the title if it is found lacking. (5) Trust Deed. A deed which established a trust. It generally is an instrument which conveys legal title to property to a trustee and states his authority and the conditions binding upon him in dealing with the property held in trust. Frequently trust deeds are used to secure lenders against loss. In this respect they are similar to mortgages.
DENDROLOGY
The branch of botany dealing with trees and shrubs.
DIGITIZING[GIS]
This involves the conversion of analog data from existing map sheets into digital (coordinated) data by using a cursor on a digitizing table.
DILUTION OF PRECISION (DOP)[GPS]
An indication of the geometric strength of the GPS trilateration solution. A smaller value represents a better geometric solution. There is positional DOP (PDOP), Geometric DOP (GDOP), Horizontal DOP (HDOP) and Vertical DOP (VDOP)
DOPPLER SHIFT[GPS]
In GPS, a systematic change in the apparent frequency of the received signal, caused by the relative movement between the satellite and the receiver.
DOUBLE CENTERING
A method of prolonging a line from a fixed point whereby the backsight is taken with the telescope in the direct position. The telescope is placed in the indirect position and the foresight is made. The point at which the vertical cross-hair intersects the hub is then marked. The transit is then rotated 180? to take a backsight with the telescope in the indirect position, and a second projected point with the telescope in the direct position is marked on the hub. A point midway between the two marked points is the true point on the prolonged line.
DOUBLE DIFFERENCING[GPS]
The GPS processing method that simultaneously measures between two GPS Recievers. This method tends to eliminate or minimize the clock errors.
DUAL FREQUENCY[GPS]
Receivers that can collect information from both the L1 and L2 carrier waves. Dual frequency allows for the modeling of Ionospheric bias, which is critical for precise measurement of long baselines.
DUE
Where monuments or other deed terms do not limit the calls, “Due north” means “astronomical north.”
EASEMENT
An interest in land created by grant or agreement which confers a right upon owners to some profit, benefit, dominion, or lawful use of or over the estate of another; it is distinct from ownership of soil. Example: an easement for road purposes.
EASEMENT, AUGMENTING
An easement lying outside the parcel being conveyed but of benefit to the parcel.
ECLIPTIC
The apparent annual path of the sun around the celestial sphere.
ELEVATION MASK ANGLE[GPS]
An elevation angle below which satellites are not tracked. Mask of 15ø is common, but more and more 10ø is used
ELLIPSE
A plane curve such that the sums of the distances of each point in its periphery from two fixed points, the foci, are equal. It is a conic section formed by the intersection of a right circular cone by a plane which cuts obliquely the axis and the opposite sides of the cone.
ELLIPSOIDAL HEIGHT[GPS]
The height above the ellipsoid of a point, measured perpendicular to the ellipsoid. This is also known as geodetic height, but it is not Orthometric or geoid height.
ELONGATION
The position of an object when it appears farthest east or farthest west from the observer’s meridian. At elongation the parallactic angle is 90?; thus the hour circle and the vertical circle through the object are perpendicular.
EMINENT DOMAIN
The right or power of government to take private property for public use on paying the owner a just compensation.
ENCROACHMENT
1) A building, a part of a building, or obstruction which intrudes upon or invades a highway or a sidewalk or trespasses upon the property of another. 2) The act of trespassing upon the domain of another. Partial, or gradual displacement of an existing use by another use; as locating factories in a residential district.
ENGINEER’S LEVEL
Any of a group of precision leveling instruments for establishing a horizontal line of sight, used to determine differences of elevation.
ENTITY[GIS]
Also called feature, this is a real-world object that can be geographically positioned or located
EPHEMERIS
1) A publication giving coordinates of celestial bodies at uniform time intervals; the coordinates are usually given for one calendar year. A publication giving similar information in a form suitable for use by a navigator is called an almanac. 2) An ephemeris is also a statement, not necessarily in a publication, presenting a correlation of time and position of celestial bodies.
EPHEMERIS[GPS]
A table of values including locations and related data from which it is possible to derive satellites position and velocity. GPS satellites broadcast an approximate ephemeris of the predicted values. Precise ephemerides can be downloaded afterwards for a more precise solution.
EPOCH[GPS]
A time interval. In GPS it is the time in seconds between observations.
EQUAL-ALTITUDE OBSERVATIONS
Observation of celestial objects at a fixed altitude (such as by an astrolabe) taken at more or less uniformly spaced azimuths around the horizon. The purpose is to obtain a number of lines of position by a method somewhat free from the effects of vertical refraction.
EQUATION OF TIME
The difference between Apparent Time and Mean Time.
ET = AT – MT
EQUATOR
The great circle in a plane perpendicular to the earth’s axis of rotation. It is located halfway between the poles and has a 0? latitude.
EQUINOX, AUTUMNAL
That point of intersection of the ecliptic and the celestial equator occupied by the sun as it changes from the northern hemisphere to the southern hemisphere, on or about September 23, or the instant this occurs.
EQUINOX, VERNAL
That point of intersection of the ecliptic and the celestial equator occupied by the sun as it changes from the southern hemisphere to the northern hemisphere, on or about March 21, or the instant this occurs.
EROSION
Wearing away of the lands or structures by running water, glaciers, winds, and waves; can be subdivided into three processes; corrasion, corrosion, and transportation. Weathering, although sometimes included here, is a distinct process which does not imply removal of any material.
ERROR
The difference between an observed or computed value of a quantity and the ideal or true value of that quantity. Because the ideal or true value of a quantity, with few exceptions, cannot be known with exactness, the term error is applied to a difference between an observed or computed value of a quantity and some standard or accepted value used in lieu of the ideal or true value. Exceptions: The ideal or true value of a quantity can be known with exactness when it is 1) mathematically determinable, independent of observation–as for example, the sum of the three angles of a plane triangle is 180?; 2) a conventional value established by authority–as for example, the length of the meter (unit) defined by the International Prototype Meter at the International Bureau of Weights and Measures. Errors are of various kinds, depending on how and where they originate. The term error with appropriate adjective or qualifying clause is used to designate the type of error–accidental error, error of observation, etc.
ERROR, ACCIDENTAL (RANDOM)
An error, also designated as a random error, produced by irregular causes whose effects upon individual observations are governed by no fixed law connecting them with circumstances and which therefore can never be subjected to a priori computation. Characteristics of accidental errors are: 1) small errors occur more frequently than large errors; and 2) there are as many negative errors as positive errors. The theory of errors, including the method of least squares, applies to accidental errors only.
ERROR, COMPENSATING
An error that tends to offset a companion error and thus obscure or reduce the effect of each.
ERROR, PROBABLE
An indication of the precision of any single observation in a series of measurements. It is a function of the accidental errors attending the individual observations in the series. An error of such magnitude that the likelihood of its being exceeded in a set of observations is equal to the likelihood of its not being exceeded; its value is that of the mean-square error multiplied by 0.6745.
ERROR, SYSTEMATIC
An error whose algebraic sign and, to some extent, magnitude bear a fixed relation to some condition or set of conditions. They always follow some definite mathematical or physical law, and they are generally eliminated from a series of observations by computation or by systematic field methods. Also called regular error.
ESTOPPEL
The stopping of a person from asserting a claim by reason of his own previous representations which refute his new claim. The new claim may in fact be true, however, he may be prevented from exerting that claim by “estoppel”.
EVIDENCE
That which is legally submitted to a competent tribunal as a means of ascertaining the truth of any alleged matter of fact under investigation before it; means of making proof; medium of proof.
EVIDENCE, EXTRINSIC
Extrinsic evidence is evidence of matter not contained in the writings, but offered to clear up an ambiguity found to exist when applying the description to the ground.
EXCEPTION/EXCEPTING
An exception withdraws a part of the thing described as granted, and which would pass but for the excepting clause. The word “except” means “not included.” “Lot 12, excepting the east 30 feet” clearly conveys that portion of Lot 12 lying westerly of the east 30 feet. “Lot 12 and Lot 13, except the east 30 feet” is not clear since the exception might apply to either one lot or both. “Lot 12 and Lot 13, except the east 30 feet of Lot 13” is better. Often used interchangeably with reserving in legal descriptions.
FEE SIMPLE
An estate of inheritance in land without qualifications or restrictions as to the persons who may inherit it as heirs. Also called an absolute fee or fee title.
FIDUCIAL MARKS (PHOTOGRAMMETRY)
Index marks, at least four, rigidly connected with the camera lens through the camera body and forming images on the negative which generally define the principal point of the photograph. Also, those marks, usually four in number, in any instrument which define the axes whose intersections fix the principal point of a photograph or negative and fulfill the requirements of interior orientation.
FOCAL LENGTH
A general term for the distance between the center, vertex, or rear node of a lens (or the vertex of a mirror) and the point at which the image of an infinitely distant object comes into critical focus. The term must be preceded by an adjective such as Aequivalent@ or Acalibrated@ to have precise meaning.
GEODESIC LINE (GEODESIC)
A line of shortest distance between any two points on any mathematically defined surface. A geodesic line is a line of double curvature, and usually lies between the two normal section lines which the two points determine. If the two terminal points are in nearly the same latitude, the geodesic line may cross one of the normal section lines. It should be noted that, except along the equator and along the meridians, the geodesic line is not a plane curve and cannot be sighted over directly. However, for conventional triangulation the lengths and directions of geodesic lines differ inappreciably from corresponding pairs of normal section lines.
GEODESY
The science which treats mathematically of the figure and size of the earth. The term is often used to include both the science, which must depend on determinations of the figure and size of the earth from direct measurements made on its surface (triangulation, leveling, astronomic, and gravity determinations), and the art, which utilizes the scientific determinations in a practical way and is usually known as geodetic surveying or geodetic engineering.
GEOID
The figure of the earth considered as a sea level surface extended continuously through the continents. It is a theoretically continuous surface that is perpendicular at every point to the direction of gravity (the plumb line). It is the surface of reference for astronomical observations and for geodetic leveling.
GNSS (GLOBAL NAVIGATION SATELLITE SYSTEM)[GPS]
A term to define all satellite navigation system including GPS
GPS RECIEVER[GPS]
A unit that captures modulated GPS signals to derive measurement of time, position and velocity
GPS TIME[GPS]
The time system used by GPS. On January 1, 1980 it was the same as UTC time. UTC adjust leap seconds to keep time synchronized with the earth?s rotation. GPS time does not adjust for leap seconds, but does keep track of the variation as a part of the navigation message
GRID LENGTH (GRID DISTANCE)
The distance between two points as obtained by computation from the plane-rectangular coordinates of the points. In the state coordinate systems, a grid length differs from a geodetic length by the amount of a correction based on the scale factor for the given line.
HORIZON
That great circle on the celestial sphere midway between the zenith and nadir. (The plane perpendicular to the zenith-nadir line and passing through the center of the observer’s transit.)
HOUR ANGLE
The angle between the plane of the hour circle passing through a celestial body or point and the plane of the celestial meridian. The hour angle is reckoned from the meridian (0 hrs. or 0?) westward through 24 hours (360?, 400g). It may be measured by the angle at the pole between an hour circle and the meridian, or by the arc of the equator which is intercepted by those circles.
HOUR ANGLE, GREENWICH
Angular distance measured westward in the plane of the equator from the upper branch of the Greenwich celestial meridian to the hour circle of a point on the celestial sphere. Varies from 0? to 360?. Symbolized by GHA.
HOUR ANGLE, LOCAL
Angular distance measured westward in the plane of the equator from the upper branch of the Observer’s Meridian to the hour circle of a point on the celestial sphere. Varies from 0? to 360?. Symbolized by LHA.
HOUR ANGLE, SIDEREAL
Angular distance measured westward in the plane of the equator from the Vernal Equinox to the hour circle of a point on the celestial sphere. Varies from 0? to 360?. Symbolized by SHA.
HOUR CIRCLE
A great circle passing through the celestial poles on the celestial sphere. It is in a plane perpendicular to the plane of the celestial equator.
HYPERBOLA
The set of points in a plane whose distances to two fixed points in the plane have a constant difference; a curve consisting of two distinct and similar branches, formed by the intersection of a plane with a right circular cone when the plane makes a greater angle with the base than does the generator of the cone.
INCUMBRANCES
The term incumbrances includes taxes, assessments, and all liens upon real property.
INTENT
The true meaning. The intent of a deed is determined from the written words only.
IONOSPHERE[GPS]
The layer of atmosphere between roughly 50 and 1000 Kilometers above the earth?s surface. The apparent speed, polarization and direction of the GPS Signals are affected within this band.
ISOGONIC MAP
A map or chart showing isogonic lines properly labeled with their magnetic declinations. Lines of equal annual change in the declinations are generally shown also.
KINEMATIC POSITIONING[GPS]
A version of relative positioning in which one receiver is stationary (Base) and at least one receiver is moving (Rover). This requires the rover to maintain lock with satellites, or re-initialize.
LATENCY[GPS]
The time between measurement and corrections being sent to a real time rover.
LATITUDE
The angular distance of a parallel North or South of the equator. Latitude varies from 0? to 90?. North latitudes are given a (+) sign and South latitudes are given a (-) sign.
LATITUDE, ASTRONOMIC
The angle between the plumb line and the plane of the celestial equator. Also defined as the angle between the plane of the horizon and the axis of rotation of the earth. Astronomic latitude is the latitude which results directly from observations of celestial bodies, uncorrected for deflection of the vertical (station error) which, in the United States, may be as great as 26″. Astronomic latitude applies only to positions on the earth and is reckoned from the astronomic equator (0?), north and south through 90?.
LAYER[GIS]
In a GIS, a layer is a collection of similar (thematic) data for a given geographic area, which is stored in a specific location in computer memory
LEAST SQUARES
A mathematical method for the adjustment of observation, based on the theory of probability. In this method, the sum of the squares of all the corrections or residuals derived for the observed data is made a minimum.
LIFE ESTATE
An estate in property, the duration of which is confined to the life of one or more persons or contingent upon certain happenings.
LINE[GIS]
A one-dimensional entity that directly links two coordinated end points
LINK[GIS]
A one-dimensional topological entity that directly connects two nodes. A directed link defines direction from a from node to a to node. See arc.
LITTORAL
Of or pertaining to, a shore, especially a seashore. More specifically applied to the depth zone of the sea floor lying between tide levels.
LOCATIVE CALLS (See CALL)
In descriptions of land locative calls are specific calls to determine location. In harmonizing conflicting calls in a deed or survey of lands, courts will ascertain which calls are locative and which are merely directory, and conform the lines to the locative calls; directory calls being those which merely direct to a neighborhood where the definite calls may be found, whereas locative calls fix boundaries (143 Tenn. 667).
LONGITUDE
The angular distance of a meridian either East or West of the prime meridian. Longitude varies from 9? to 180?.
LONGITUDE, ASTRONOMIC
The angle between the plane of the celestial meridian and the plane of an initial meridian, arbitrarily chosen. Astronomic longitude is the longitude which results directly from observations on celestial bodies, uncorrected for deflection of the vertical, the prime vertical component of which, in the United States, may amount to more than 19″. Astronomic longitude is measured by the angle at the celestial pole between the tangents to the local and initial meridians, or by the arc intercepted on the equator by those meridians.
LOWER BRANCH
That half of a meridian or celestial meridian from pole to pole which passes through the observer’s antipode or his/her nadir.
LOWER TRANSIT
Movement of a celestial body across the lower branch of the observer’s meridian.
MAIN CHANNEL
The middle, deepest or best navigable channel (state boundary lines are sometimes along the main channel which may not be half way between the banks).
MEAN HIGH WATER
The mean height of tidal high waters at a particular station for 18.6 or 19 years. Along rivers it has various meanings and is usually a gradient (decreases in elevation downstream) boundary. Practical definitions are: where vegetation ceases, etc.
MEAN SOLAR DAY
The interval of time between two successive lower transits of the Mean Sun over the same meridian.
MEAN SUN
A fictitious sun which travels at a uniform rate along the celestial equator. (The Mean Sun is sometimes ahead of and sometimes behind the Apparent Sun.)
MEAN TIME
The Hour Angle of the Mean Sun, with respect to the lower limb of some meridian.
MEANDER LINE
Meander line is a traverse of a body of water for the purpose of determining the size and location of the body of water. For riparian owners meander lines do not represent the boundary line; the body of water where it exists represents the true boundary lines. When meander lines are nonriparian, they may become land boundary lines.
MERIDIAN
A great circle which passes through the earth’s North and South poles. They are named or considered as half circles extending from pole to pole on the side of the earth where the observer is located.
MERIDIAN ANGLE
The angular distance measured in the plane of the equator from the upper branch of the Observer’s Meridian to the hour circle of a celestial body, measured eastward or westward up to 180?, and labeled E or W to indicate the direction of measurement. Symbolized by “t”.
If the star is West of the Observer, then t = LHA.
If the star is East of the Observer, then t = 360° LHA.
MERIDIAN, ASTRONOMIC
A line on the surface of the earth having the same astronomic longitude at every point. Because the deflection of the vertical is not the same at all points, an astronomic meridian is an irregular line, not lying in a single plane. The astronomic meridian and the line whose astronomic azimuth at every point is south or north (0? or 180?) are not necessarily coincident, although in land surveying the term astronomic meridian is sometimes applied to the north-south line which has its initial on a prescribed astronomic meridian.
METES AND BOUNDS
As commonly understood, a description of real property which is not described by reference to a lot or block shown on a map, but is defined by starting at a known point and describing, in sequence, the lines forming the boundaries of the property.
MONUMENTS
Monuments as pertaining to land surveying are tangible landmarks indicating land boundaries. (1) Physical Monuments. A physical monument is an existing feature such as a stone, stake, tree, hill, ocean, river, or lake, but not the unmarked line of an adjoiner. (2) Natural Monuments. A natural monument is a naturally occurring object such as a lake, river, tree, boulder, or hill. Although the courts sometimes refer to a record monument (land of adjoiner) as a type of natural monument, such a broad meaning is excluded in these pages. (3) Artificial Monument. An artificial monument is a manmade object such as a stake, fence, set stone, etc. (4) Record Monument. An adjoiner property called for in a deed such as a street or particular parcel of land. Frequently the boundary line of the adjoiner is referred to as the record monument; actually the entire property, rather than the line, is the monument. Physical monuments may or may not mark a record monument. In court reports, record monuments are often referred to as natural monuments, but such a meaning is excluded in these pages. A record monument is often referred to as an adjoiner. Usually a record monument has senior standing, though not always. (5) Legal Monument. Any monument controlling in a legal description. It is often limited in meaning so as to be synonymous with record monument.
MORE OR LESS
The words more or less in their ordinary use are to be taken as words of caution, denoting some uncertainty in the mind of one using them and a desire not to misrepresent. When used in connection with quantity and distance, more or less are words of safety and precaution, intended merely to cover some slight or unimportant inaccuracy. When “125 feet more or less to the point of beginning” is used in a deed, the more or less indicates that the 125 feet is an informative term, whereas “to the point of beginning” is the controlling term. “About 12 acres more or less” is indefinite and should be avoided since the word “about” is very broad in meaning.
MULTIPATH[GPS]
The error caused by GPS receivers picking up reflected GPS signals. The reflected signal traveled longer distance, which causes averaged distance to be longer then true.
NADIR
1) That point on the celestial sphere vertically below the observer, or 180? from the zenith. HO 220, USNOO 35.2 (photogrammetry). The point on the ground or at sea level datum vertically beneath the perspective center of the camera lens, or the photographic image of that point. On the photograph it is the center of radiation for displacement of images because of ground relief. Also called plumb point.
NAVIGATION MESSAGE[GPS]
The GPS message that provides Ionospheric model, ephemeris, clock correction, constellation almanac, and satellite health
NETWORK[GIS]
An entity of inter-connected lines that permits the analysis of route flow.
NODAL POINTS (OPTICS, PHOTOGRAPHY)
Two points associated with a lens system, such that any ray in the object space directed toward the first or front point will emerge in the image space from the second or rear point and parallel to its former direction. The points are also termed nodal point of incidence and nodal point of emergence, respectively, and they establish the optical axis of the system.
NODE[GIS]
A zero-dimensional topological point entity which represents a beginning or ending of chains (representing arcs or lines) – including intersections.
NORTH
“Though the word North, as used in the descriptive call of a deed, may be controlled or qualified in its meaning by other words of description used with it, yet when it is not qualified by other words, it must be construed as meaning due North”. Due North means geographical or astronomical north, not geodetic north.
NORTHERLY
Where nothing is given to limit the exact direction, northerly means due north. Directional calls as northerly are often given in deeds to avoid ambiguity as “thence westerly along Jones Creek to the thread of Merrimack River; thence northerly along Merrimack River; etc.”
OBSERVER’S MERIDIAN
The great circle on the celestial sphere which passes through the North and South celestial poles and the observer’s zenith and nadir.
ON-THE-FLY (OTF)[GPS]
Resolving integer ambiguity while moving. This requires a dual frequency receiver capable of both carrier phase and pseudoranging.
ORDINARY TIDES
This expression is not used in a technical sense by the National Ocean Survey but the word Aordinary@ when applied to tides may be taken as the equivalent of the word Amean.@ Thus, Aordinary high water line@ may be assumed to be the same as Amean high water line.@
ORTHOMETRIC HEIGHT[GPS]
The vertical distance from the geoid to a point, measured perpendicular to the geoid or along a vertical line.
OVERLAY[GIS]
The GIS techniques of selectively comparing and combining layers (categories) of entities and their variable attributes for a specified ground area, which have been stored on separate thematic layers.
PARABOLA
A plane curve formed by the intersection of a right circular cone with a plane parallel to a generator of the cone; the set of points in a plane that are equidistant from a fixed line and a fixed point in the same plane or in a parallel plane.
PARALLEL
A small circle in a plane perpendicular to the earth’s axis.
PAROLE EVIDENCE
Evidence gathered by testimony of witnesses.
PATENT (noun)
The title conveyed by the government describing land disposed of by the government; a quitclaim from the government in the form of a patent.
P-CODE[GPS]
The precise code used by the military. Civilian receivers do not have access to this code.
PIXEL[GIS]
Like a raster grid cell, a pixel (picture element) is the basic element of a digital image (e.g., satellite image or scanned image) – whose resolution represents a defined amount of geographic space. See Chapter 13, Satellite Imagery.
POINT
Point in a boundary is the extremity of a line. “To a point” in a description is often meaningless, since the end of a line is a point. If the point is to be referred to later, “to point A” or “to point #1” gives an easy later reference.
POINT[GIS]
A zero-dimensional entity that specifies geometric location (e.g., by coordinates)
POLAR DISTANCE
The complement of the declination (co-declination) or 90? minus the declination. Polar distance forms one side, celestial body to pole, of the astronomical triangle.
POLARIS
The second-magnitude star, Alpha, in the constellation Ursa Minor (Little Dipper). Also known as the polestar, or north star, because of its proximity to the north pole of the celestial sphere. Polaris is well situated for determinations of astronomical azimuth, and for the determination of the direction of the celestial meridian. It is at the extreme outer end of the handle of the “Little Dipper.”
POSITION, ASTRONOMICAL
1) A point on the earth whose coordinates have been determined as a result of observations of celestial bodies. The expression is usually used in connection with positions on land determined with great accuracy for survey purposes. 2) A point on the earth, defined in terms of astronomical latitude and longitude.
PRECISION
The degree of refinement in the performance of an operation, or the degree of perfection in the instruments and methods used when making the measurements. A measure of the uniformity or reproducibility of the result. Precision relates to the quality of the operation by which a result is obtained, and is distinguished from accuracy which relates to the quality of the result.
PRESCRIPTION
Title obtained in law by long possession. Occupancy for the period prescribed by the Code of Civil Procedure, as sufficient to bar an action for the recovery of the property, gives title by prescription.
PRIMA FACIE EVIDENCE
Evidence deemed by law to be sufficient to establish a fact if the evidence is not disputed.
PRIME MERIDIAN
The one meridian selected for the origin of East-West angular measurements. It has 0? longitude.
PROPORTIONATE MEASUREMENT
A measurement that applies an even distribution of a determined excess or deficiency of measurement, ascertained by retracement of an established line, to provide concordant relations between all parts.
PROPORTIONATE MEASUREMENT, DOUBLE
A method for restoring a lost corner of 4 townships or a lost interior corner of 4 sections. It is based on the principle that monuments north and south should control the latitudinal position of a lost corner, and monuments east and west should control the longitudinal position. In this method the influence of one identified original corner is balanced by the control of a corresponding original corner upon the opposite side of a particular missing corner, which is to be restored, each identified original corner being given a controlling weight inversely proportional to its distance from the lost corner.
PROPORTIONATE MEASUREMENT, SINGLE
A method of proportioning measurements in the restoration of a lost corner whose position is determined with reference to alinement in one direction. Examples of such corners are–quarter-section corners on the line between two section corners, all corners on standard parallels, and all intermediate positions on any township boundary line. The ordinary field problem consists of distributing the excess of deficiency between two existent corners in such a way that the amount given to each interval shall bear the same proportion to the whole difference as the record length of the interval bears to the whole distance. After having applied the proportionate difference to the record length of each interval, the sum of the several parts will equal the new measurement of the whole distance.
PRORATION
A method of distributing discovered excess or deficiency between parties having equal rights or proportionate rights to the excess or deficiency. A method of calibrating the tape of a recent surveyor against that of the original surveyor.
PSEUDORANDOM NOISE (PRN)[GPS]
A sequence of digital 1s and 0s that appear random, but can be reproduced exactly. Each satellite has a unique PRN for the C/A and P code. The satellites are often identified by their PRN
PSEUDORANGE[GPS]
In GPS a time biased distance measurement based on the PRN code transmitted by the GPS satellite, collected by the GPS Receiver and then correlated to determine the difference in time between transmission and reception.
QUIET TITLE
An action at law to remove an adverse claim or cloud on the title of property.
RADIAN
The angle subtended at the center of a circle by an arc equal in length to a radius of the circle. It is equal to 360? ? 2π, or approximately 57?17’44.8″.
REAL TIME KINEMATIC POSITIONING (RTK)[GPS]
A method of relative positioning with GPS that provides almost real time high precision solutions. Advancements such as OTF solutions, makes this the most common method used in surveying today.
RELATIONAL DATABASE[GIS]
A database which stores attribute and spatial data in the form of tables which all can be linked through a common identifier (e.g., primary key) – such as a coordinated spatial locator.
RELICTION
The gradual and imperceptible recession of the water resulting in an uncovering of land once submerged. Also known as dereliction.
RESERVATION (in a deed)
A taking back or withholding by the grantor of some interest in the property conveyed by the deed; distinguished from an exception, which is a definite refusal to grant any certain interest. Reservations are used in preference to exception, which is a definite refusal to grant any certain interest. Reservations are used in preference to exceptions in creating separate estate in easements, rights-of-way, and similar matters.
RESERVING
When a thing granted is taken back, it is reserved. Easements are usually reserved, as “reserving a 20-foot easement for road purposes, etc.” Reserving is used when a new encumbrance is being created. A reservation creates some right or privilege for the grantor in the land described as granted.
REVULSION
A strong pulling or drawing back or away; withdrawal. A strong or sudden reaction, reversion, or change.
RIGHT ASCENSION
Angular distance east of the vernal equinox; the arc of the celestial equator, or the angle at the celestial pole, between the hour circle of the vernal equinox and the hour circle of a point on the celestial sphere, measured eastward from the hour circle of the vernal equinox in units of hours, minutes, seconds.
RIGHT-OF-WAY
Right to use or cross over property of another.
RINEX[GPS]
Receiver Independent Exchange Format. A package of GPS data formats and definitions that allow interchangeable use of data from dissimilar receiver models and postprocessing software.
RIPARIAN
Of or on the bank; related to or belonging to the bank of a river. Also now used along the seashore.
RIPARIAN RIGHTS
The right that an owner of land bordering on a river has in the water flowing in the river or the land underneath the river. Also the rights of a person owning land bordering on a body of water in or to its banks, bed, water, or travel on the water.
ROUTING[GIS]
Networks are analysed to determine optimal travel paths or flow from one point to another.
RTCM[GPS]
Radio Technical Commission on Maritime Services. In DGPS, this is a standardize form of sending the GPS signal for correction. Most all DGPS receivers can read RTCM coded corrections.
RUBBER SHEETING[GIS]
This is a process of arbitrarily reconciling (stretching) data from different sources which may not fit perfectly together because of problems occasioned by differing scales, orientations, and projections.
SAID
Said refers to one previously mentioned with the same name.
SCALE[GIS]
In GIS and mapping, scale refers the size ratio between a ground distance or area and the depiction of that ground distance or area on a map or raster grid.
SCANNER[GIS]
This is a raster input device which scans a document one line at a time and records the location of scanned objects in a raster matrix.
SCRIVENER
Professional writer, deed author.
SEGMENTATION[GIS]
This is the creation of new lines or arcs as changes occur to the original line or arc – such as occurs when there is a change in attributes (a two-lane road becomes a 4-lane road, or a valve is inserted into a water distribution line) or the creation of new segments caused by intersecting lines or polygons.
SELECTIVE AVAILABILITY (SA)[GPS]
This is a degradation of the precisionl by dithering the timing and ephermides data in the satellites. The intentional degradation begun in 1990 and was finally switched off in 2000
SENIOR RIGHTS
The rights in a parcel of land, or several parcels, created in sequence with a lapse of time between them. A person conveying part of his land to another (senior) cannot, at a later date, convey the same land to another (junior). A buyer (senior) has a right to all land called for in a deed, the seller (junior) owns the remainder.
SIDEREAL DAY
The interval of time between two successive upper transits of the Vernal Equinox over the same meridian.
SIDEREAL TIME
The Hour Angle of the Vernal Equinox, with respect to some meridian.
SPHERICAL EXCESS
The amount by which the sum of three angles of a triangle on a sphere exceeds 180?. The magnitude of the excess depends upon the radius of curvature and the area of the triangle, and is approximately one second of arc for each 75.6 square miles on the spheroid of the earth. Spherical angles are generally used in geodetic surveying and the difference between spherical and spheroidal angles is neglected. One-third of the spherical excess is subtracted from each angle, or Legendre’s theorem is applied in distribution of the spherical excess.
STATIC POSITIONING[GPS]
A relative differential surveying method in which at least two stationary GPS receivers collect data simultaneously from the same satellites during a long observation period.
STRING[GIS]
A sequence of line segments
SUBDIVISION (real estate)
An unimproved tract of land surveyed and divided into lots for purposes of sale. In some localities it is distinguished from a development, upon which improvements are made before sale; in other localities the terms are synonymous.
SUBDIVISION (USPLS)
The subdivision of a township, such as a section, half-section, quarter-section, quarter-quarter or sixteenth-section, or lotting, including the lot, section, township, and range numbers, and the description of the principal meridian to which referred, all according to the approved township plat.
SUBJECT TO
Subject to refers to something already existing, as “subject to an easement.”
SURVEYING, GEODETIC
That branch of the art of surveying in which account is taken of the figure and size of the earth. Also called geodetic engineering.
SV [GPS]
Space Vehicle
TANGENT
A tangent to a curve is a line that touches the curve at one point and also is at right angles to the radial line at the point of contact with the curve.
THEMATIC LAYER OR MAP [GIS]
Computer storage layers or maps that display the geographic locations of spatial entities which have one or more common attributes.
THENCE
From that place; the following course is continuous from the one before it.
THEREON
A deed that granted a passageway and specified that the grantor must fence the same but reserved the right “to erect gates thereon” implied the right to erect gates either on the side or across the passageway.
THREAD
“Thread of a road” is a line midway between the side lines. “Thread of a stream” is the line midway between banks or the line equidistant from the edge of the water on the two sides of the stream at the ordinary stage of the water. Consult each state’s law for a definition within a given state.
THREAD OF RIVER (OR STREAM)
The line equidistant from the edge of the water on the two sides of the stream at the ordinary stage of the water. In some cases it has been construed to mean the median line of the main channel of the stream; the state law should be consulted in any case.
TIDAL
For water to be tidal it does not necessarily have to be salty; it must have tides that regularly flow and reflow.
TIDAL DATUM
Specific tide levels which are used as surfaces of reference for depth measurements in the sea and as a base for the determination of elevation on land. Many different datums have been used, particularly for leveling operations. Also called tidal datum plane.
TIDELANDS
All coastal areas that are situated above mean low tide and below mean high tide, particularly as such areas are alternately uncovered and covered by the ebb and flow of the ordinary daily tides.
TIGER[GIS]
Topologically Integrated Geographic Encoding and Referencing System – this is a topological data model designed by the U.S. Bureau of Census. Much data digitized for this model have come from small scale USGS maps.
TIME
1) Finite duration. 2) The hour of the day reckoned by the position of a celestial reference point relative to a reference celestial meridian. Time may be solar, lunar, or sidereal as the reference is the sun, moon, or vernal equinox, respectively. Solar time may be further classified as mean if the mean sun is the reference; or as apparent if the apparent sun is the reference. Time may also be classified according to the reference meridian, either the local or Greenwich meridian or additionally in the case of mean solar time, a designated zone meridian. Standard, daylight savings or summer, and war time are variations of zone time. Time may also be designated according to the time piece, as chronometer time or watch time, the time indicated by these instruments. 3) An elapsed interval.
TIME, CIVIL
Solar time in a day (civil day) that begins at midnight. Civil time may be either apparent solar time or mean solar time; it may be counted in two series of 12 hours each, beginning at midnight, marked “a.m.” (ante meridian), and at noon, marked “p.m.” (post meridian), or in a single series of 24 hours beginning at midnight.
TIME, COORDINATED UNIVERSAL (UTC)
Time measured according to the Mean Sun with respect to the lower branch of the Greenwich meridian, and adjusted for a variety of influences. Also called Greenwich Mean Time (GMT), Greenwich Civil Time (GCT), and Zebra or Zulu Time (ZT).
TIME, GREENWICH MEAN
Mean solar time of the meridian of Greenwich, used by most navigators, and adopted as the prime basis of standard time throughout the world.
TIME, LOCAL
1) Time based upon the local meridian as reference, as contrasted with that based upon a time zone meridian, or the meridian of Greenwich. 2) Any time kept locally.
TIME, SIDEREAL
Time measured by the apparent diurnal rotation of the (true) vernal equinox. At any instant, sidereal time is the hour angle of the vernal equinox. It is counted from 0 hour, when the vernal equinox is on the meridian, through 24 hours. Naming the meridian of reference is essential to its complete identification–for example, 75th meridian sidereal time; Greenwich sidereal time; and local sidereal time for the meridian of the observer.
Because of small differences between the positions of the true and mean equinoxes, sidereal time, like the sidereal day, is subject to slight irregularities. These irregularities are absent from (uniform) sidereal time, which is measured by the motion of the mean equinox and is used in rating clocks of the highest precision.
TIME, SOLAR
1) Time based upon the rotation of the earth relative to the sun. Solar time may be classified as mean if the mean sun is the reference; or as apparent if the apparent sun is the reference. The difference between mean and apparent time is called equation of time. Solar time may be further classified according to the reference meridian, either the local or Greenwich meridian or additionally in the case of mean time, a designated zone meridian. Standard, daylight saving or summer, and ware time are variations of zone time. Time may also be designated according to the timepiece, as chronometer time or watch time, the time indicated by these instruments. 2) Time on the sun.
TIME, STANDARD
Mean solar time for a selected meridian adopted for use throughout a belt (zone).
In the continental U.S., the meridians of reference for standard time are 15? (1 hour) apart, and multiples of 15? from the initial meridian, Greenwich Meridian. The standard time for each belt is designated by the number of its meridian and also by some name of geographic significance: 75th meridian or Eastern Standard Time; 90th meridian or Central Standard Time; 105th meridian or Mountain Standard Time; and 120th meridian or Pacific Standard Time. Standard time was established in 1883 to correlate train schedules of various railroads over the same areas. The standard time belts were planned to be roughly symmetrical with respect to the meridians of reference, and to extend 7 1/2? to either side thereof. Practical considerations, such as the need of time correlation of cities outside the original boundaries of a time belt with cities within the belt, have caused a gradual shifting of those boundaries until some of them now exhibit large irregularities.
TIME, UNIVERSAL (U.T.)
The same as Greenwich mean time (GMT). The first use of Universal time as a reference in the American Ephemeris and Nautical Almanac is in the volume for the year 1939.
TO
“To,” “on,” “by,” “at,” and “along” a road carry title to the center line unless otherwise qualified. To implies contact. To does not always include an object, as “to a certain property” does not include the property. But “to a stone” usually means “to the center of the stone.” To is directional, as “90? to (not with)” or “at right angles to.” To is a word of exclusion rather than inclusion. If you go to an object, you exclude other objects. If you go to a house, you do not necessarily go in the house.
TRIANGULATION
A method of surveying in which the stations are points on the ground at the vertices of a chain or network of triangles. The angles of the triangles are measured instrumentally and the sides are derived by computation from selected sides or bases, the lengths of which are obtained by direct measurement on the ground or by computation from other triangles. A triangulation system of limited width (generally that of one triangle), designed to progress in a single general direction, is designated arc triangulation, and the chain of triangles (or polygons composed of abutting or overlapping triangles) is called a triangulation arc. A network of triangulation designed to cover an area with abutting or overlapping triangles is designated area triangulation, and the resulting configuration is called a triangulation net.
TRILATERATION
A method of surveying wherein the lengths of the triangle sides are measured, usually by electronic methods, and the angles are computed from the measured lengths. Compare with triangulation.
TRIPLE DIFFERENCE[GPS]
A measurement method that minimizes the potential of cycle slip by combing double differencing over 2 epochs. Therefore it requires two satellites, two receivers and two epochs.
TRIVIAL BASELINE[GPS]
Trivial baselines are created when using more than two GPS receivers simultaneously for static positioning. The number of independent (non-trivial) vectors measured is equal to the number of receivers ? 1. All other baselines are trivial. Trivial baselines, should not be used for the network adjustments as it can false weight the value of a position.
TROPOSPHERIC EFFECT[GPS]
The troposphere comprises approximately 9 km of atmosphere at the poles and 16 km at the equator. It effects both the L1 and L2 equally. The refraction in the Troposphere has both a wet and dry component to it.
UPPER BRANCH
That half of a meridian or celestial meridian from pole to pole which contains (passes through) an observer or his/her zenith.
UPPER TRANSIT
Movement of a celestial body across the upper branch of the observer’s meridian.
VERTEX[GIS]
Similar to a node, a vertex point entity signals a simple change in direction of a line or arc (but not an intersection).
VERY LONG BASELINE INFEROMETRY (VLBI)[GPS]
By measuring the arrival time of the wave front emitted by a distant quasar at two widely separated earth-based antennas, the relative position of the antenna is determined to precisions of a few millimeters.
VEST
To give title to or to pass ownership to property.
WIDE AREA AUGMENTATION SYSTEM (WAAS)[GPS]
This is a correction service for DGPS provided and maintained by the FAA.
WITH
With shows an association, as “parallel with,” not “parallel to.” With a line, meaning along a line, is commonly used in the eastern states.
WITNESS MARK (MONUMENT)
A material mark placed at a known distance and direction from a property corner, instrument, or other survey station, to aid in its recovery and identification.
In surveying, a witness mark is established as an aid in the recovery and identification of a survey station, or other point to which it is a witness. A mark which is established with such precision and accuracy that it may be used to restore or take the place of the original station is more properly called a reference mark in control surveys, and a witness corner in land surveys. Also called witness post or witness stake.
WORDS OF EXCLUSION
To, from, by, between, and on are words of exclusion unless there is something in the phrase that makes it apparent that the words were used in a different sense. “To a stone mound,” “on Brown’s land,” and “by the river” exclude other terms.
WORLD GEODETIC SYSTEM 1984[GPS]
This is the datum used by the GPS satellites. Currently the GPS system is using the G1150 adjustment
Y-CODE[GPS]
This is the encrypted P-Code.
ZENITH
That point on the celestial sphere vertically overhead of the observer.
ZENITH DISTANCE
The vertical angle between the zenith and the object which is observed or defined. Zenith distance is the complement of the altitude.
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