an image of a bronze Compass with Back Azimuth

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LAND SURVEY TERMS

GLOSSARY OF U.S. BUREAU OF LAND MANAGEMENT SURVEYING AND MAPPING TERMS F


Land Survey Terms, A convenient source for our clients and website visitors

F

[break]F – Fahrenheit; Flat

F.2d – In a citation, as 22 F.2d 100, means Federal Reporter, Second Series.

FA – Fire alarm box

FAA (Land Status Records) – Federal Aviation Administration.

FAAT – Fully Analytical Aerotriangulation

FAC – Feature analysis code(s)

FACC Feature and Attribute Coding Catalog

FBX MER (Land Status Records) – Fairbanks Meridian.

FC (Land Status Records) – Final Certificate.

FED (Land Status Records) – Federal.

FED – Federal. If shown as a citation [198 Fed. 125 (1912)], it means “Federal Reporter.”

FF LSE (Land Status Records) – Fur farm lease.

FFMC (Land Status Records) – Federal Farm Mortgage Corporation.

FHA (Land Status Records) – Farmers Home Administration.

FIS (Land Status Records) – Fissionable materials.

FL – Florida.

FLA. – Florida.

FLPMA – Federal Land Policy and Management Act, of 1976.

FLS (Land Status Records) – Forest lieu selection.

FLUP – Free land use permit.

FM U (Land Status Records) – Farm unit.

FPA (Land Status Records) – Federal Power Act.

FPAS ACT – The Federal Property and Administration Services Act of 1949, as amended, sets forth the basic
contracting procedures and principles which all civilian agencies must follow.

FPC (Land Status Records) – Federal Power Commission.

FPR – Federal Procurement Regulations.

FR (Land Status Records) – Federal Register.

FRAC (Land Status Records) – Fractional.

FRAC INT PAT (Land Status Records) – Fractional Interest patent.

FS (Land Status Records) – Forest Service.

F. SUPP. – Federal Supplement.

FUP (Land Status Records) – Free use permit.

F&WS (Land Status Records) – Fish and Wildlife Service.

FX (Land Status Records) – Forest Exchange.

F STOP – A point on the scale of graduations of lens aperture size. The function of focal length is divided by the aperture of a lens.

FALSE COLOR – Reproduction that shows objects in colors other than their true color. Usually refers to color Infrared.

FALSE ORIGIN – An arbitrary zero point to the south and west of a grid zone that is assigned to avoid negative coordinate values.

FATHOM – 1) A unit of distance equivalent to 6 feet, used primarily in marine depth measurements. 2) To find the depth of something; to sound.

FEATHERING – 1) The technique of progressively dropping contours, to avoid congestion on steep slopes. 2) The
thinning of overlapping edges of photographs before assembly into a mosaic in order to make match lines less noticeable.

FERTSCH EFFECT – A phenomenon of physiological optics that occurs with rapid scanning of a stereo model in a
direction parallel to the eye base and that appears as a vertical displacement of the floating mark which reverses
with the direction of scanning. The effect is directly related to the relative brightness of the two exposures in the
immediate vicinity of observation, and to the fact that the human eye tends to detect the movement of the floating mark more quickly in a bright background than in a dark one.

Please feel free to contact us about Land Survey Terms or any other questions. We are here now and ready to answer.


FIDUCIAL AXES – The imaginary lines defined by opposite fiducial marks on a photograph. The x-axis is
considered to be the axis nearly parallel with the flight lines.

FIDUCIAL MARKS – Those marks, which define the axes whose intersection fixes the principal point of the
photograph. See FIDUCIAL AXES.

FIELD BOARD – Slang for plane table sheet. See preferred FIELD SHEET.

FIELD CHECK (USGS) – An on-the-site comparison of the features shown on a map compilation with the ground
features.

FIELD COMPLETION (USGS) – Obtaining in the field additional information needed to edit and publish a
topographic quadrangle map from a compiled manuscript. It includes a comprehensive examination of the
compilation for completeness, quality, and topographic expression; the addition, deletion, or correction of map
features; the classification of buildings, roads, drainage, and woodland; the mapping of public-land subdivision
lines and civil boundaries; obtaining name information; and checking the map for compliance with vertical-
accuracy standards.

FIELD CONTOURING – Placing contours on a topographic map by plane table surveys on a prepared base.

FIELD COPY – See preferred FIELD SHEET.

FIELD EDIT – See preferred FIELD COMPLETION.

FIELD ELEVATION – Any elevation determined by field methods.

FIELD INSPECTION – The process of comparing aerial photographs with conditions as they exist on the ground
and of obtaining information to supplement or clarify that which is not readily discernible on the photographs
themselves.

FIELD PHOTOINTERPRETATION – The operation of annotating aerial photographs in the field to clarify
uncertain photo images, to add details not discernible on the photographs, and to delete features appearing on
photographs not map-worthy or no longer present on the ground. See ADVANCE FIELD COMPLETION.

an image of a white circular Compass with Back Azimuth
FIELD POSITION (USGS) – 1) A position determined by fieldwork. 2) A position computed while fieldwork is in progress.

FIELD SHEET (USGS) – A sheet of stable material generally used on a plane table, either blank or with compiled data, on which fieldwork is plotted. Also called a plane table sheet. In field completion surveys, it contains the compilation to be completed.

FIELD SKETCHING (USGS) – The art of drawing or filling in map detail based on selected positions and
elevations plotted on a plane table sheet.

FILL – Use of material to equalize or to raise topography to a certain grade; to build up with fill; to fill the low ground with sand, gravel, or earth; the material used to artificially raise topography.

FILM BASE – A thin flexible transparent sheet of material used as a support for photographic emulsion.

FILM DISTORTION – The nonuniform dimensional changes which occur in photographic film with changes in humidity or temperature, or from aging, handling, or other causes. (Note: The failure of film to be flat in the camera at the instant of exposure is sometimes referred to, incorrectly, as film distortion. Although lack of flatness may result in errors on the photograph similar to those caused by film distortion, the cause of these errors is incomplete functioning of the pressure or vacuum system of the camera rather than dimensional instability of the film.)

FILM MOSAIC (USGS) – An assembly of film negatives or positives of a map manuscript adjusted and fitted to a
map projection constructed on a transparent base.

FILTER – 1) An electronic device for eliminating or reducing certain waves or frequencies while leaving others relatively unchanged. 2) Any material which modifies radiation transmitted through an optical system by absorption, reflectance, polarizing or scattering.

FIORD – A long, narrow inlet into the sea coast, with more or less steep sides.

FIRST ORDER – The designation is given survey work or equipment which conforms to the highest standards of
precision and accuracy. See CONTROL SURVEY CLASSIFICATION.

FIRST ORDER MAGNITUDE RELIEF FEATURE – A continent or an ocean basin.

FIRST ORDER PLOTTER – An obsolescent term originally designating a stereo instrument capable of performing aero triangulation.

FIXED – A descriptive term used with a benchmark, point, position, station, etc., to designate a point for which
geodetic coordinates (latitude and longitude, or elevation) have been established by a previous adjustment or by
a more precise survey and are to be held without disturbance in a newer survey or adjustment. See FIXED
BOUNDARY*.

FIXING – The process of rendering a developed photographic image permanent by chemically removing the
unaffected light-sensitive material.

FLAT – 1) A level surface, without elevation, relief, or prominences; a plain; a level tract along the banks of a river.
2) A level tract lying at little depth below the surface of the water, or alternately covered and left bare by the
tide. See OPTICAL FLAT.

FLATNESS OF FIELD – The quality of a lens that affords sharpness of image both in the center and at the edges
of a negative.

<span style=”font-family: arial, helvetica, sans-serif; font-size: 18px;”><span style=”color: #004fbd;”><img class=”alignleft wp-image-9816″ src=”https://haller-blanchard.com/wp-content/uploads/2021/12/the-safe-companies-contact-us.gif” alt=”” width=”38″ height=”38″ />Please feel free to</span> <a href=”https://haller-blanchard.com/contact-land-survey-company//”>contact us</a> <span style=”color: #004fbd;”>about Land Survey Terms or any other questions. </span></span><span style=”font-family: arial, helvetica, sans-serif; font-size: 18px;”><span style=”color: #004fbd;”>We are here now and ready to answer.</span>
</span>

FLICKER METHOD – The alternative projection of corresponding photographic images onto a tracing-table
platen or projection screen, or into the optical train of a photogrammetric instrument. See STEREO IMAGE
ALTERNATOR.

FLIGHT ALTITUDE – The vertical distance above sea level of an aircraft in flight. In aerial navigation practice,
the altitude of an aircraft is always stated in relation to the sea level. See FLIGHT HEIGHT.

FLIGHT HEIGHT (OR FLYING HEIGHT) – The vertical distance between an aircraft in flight and the mean
the ground level of the area being photographed.

FLIGHT HEIGHT TO CONTOUR INTERVAL RATIO – See C FACTOR.

FLIGHT LINE – A line drawn on a map or chart to represent the planned or actual track of an aircraft.

FLIGHT MAP – A map on which are indicated the desired flight lines and (or) the positions of exposure stations
before aerial photographs are taken, or a map on which are plotted, after photography, selected air stations and
the tracks between them.

FLIGHT SPACING – The distance between adjacent tracks in a series of parallel aircraft flights.

FLIGHT STRIP – A succession of overlapping aerial photographs taken along a single course.

FLOATING MARK – A mark is seen as occupying a position in the three-dimensional space formed by the
stereoscopic fusion of a pair of photographs and used as a reference mark in examining or measuring the
stereoscopic model. The mark may be formed (1) by a real mark lying in the projected object space, (2) by two
real marks lying in the projected or virtually projected object spaces of the two photographs, (3) by two real
marks lying in the planes of the photographs themselves, and (4) by two virtual marks lying in the image planes
of the binocular viewing apparatus.

Please feel free to contact us about Land Survey Terms or any other questions. We are here now and ready to answer.

FLOOD-PLAIN – A plain, bordering a river, which has been formed from deposits of sediment carried down by the
river. When a river rises and overflows its banks, the water spreads over the floodplain; a layer of sediment is
deposited at each flood so that the floodplain gradually rises.

FLY LEVELING – Spirit leveling in which some of the restrictions of precise leveling, such as limiting lengths of
sights and balancing backsight and foresight distances are relaxed to obtain elevations of moderate accuracy
more rapidly.

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 ”equivalent” or “calibrated” to have a precise meaning. See BACK
FOCAL LENGTH, CALIBRATED FOCAL LENGTH, EFFECTIVE FOCAL LENGTH, EQUIVALENT

FOCAL LENGTH and NORMAL FOCAL LENGTH.

FOCAL PLANE – The plane perpendicular to the optical axis of the lens in which images of points in the object
field is focused.

FOCUS – The point toward which rays of light converge to form an image after passing through a lens or reflecting
from a mirror. Also defined as the condition of the sharpest imagery. See DEPTH OF FOCUS.

FOOT-METER ROD (USGS) – A stadia rod graduated in feet on one side and in meters on the other.

FOOT PLATE – A metal plate with a knob used as a turning point in leveling across the sand.

FORESIGHT – 1) A sight on a new survey point in connection with a survey, or on a previously established point
to close a circuit. 2) In leveling, a reading on a rod is held on a point to determine its elevation. See SIDE SHOT
and FORESIGHT*.

FORMAT – 1) The dimensions of the negative area within the focal-plane frame of the camera. 2) The dimensions
of a map.

FORMAT CENTER – The point near the center of a photograph at the intersection of the lines between fiducial
marks.

FORM LINES – Lines resembling contour lines, drawn to represent the shape of the terrain but without regard to
true vertical datum or regular spacing.

FOUND CORNER – A term adopted by the U.S. Geologic Survey for an existent corner of the Public Lands
Surveys which have been recovered by field investigation. See CORNER*.

FRACTIONAL SCALE – A map scale expressed as a fraction, as 1/24,000. See REPRESENTATIVE
FRACTION.

FREQUENCY – Number of repetitions of a periodic process per unit of time.

FUSION – That metal process that combines the two perspective images on the retinas of the eyes in such a manner as to give a mental impression of the three-dimensional model.

Please feel free to contact us about Land Survey Terms or any other questions. We are here now and ready to answer.

LAND SURVEY TERMS

GLOSSARY OF U.S. BUREAU OF LAND MANAGEMENT SURVEYING AND MAPPING TERMS F


Land Survey Terms, A convenient source for our clients and website visitors

F

[break]F – Fahrenheit; Flat

F.2d – In a citation, as 22 F.2d 100, means Federal Reporter, Second Series.

FA – Fire alarm box

FAA (Land Status Records) – Federal Aviation Administration.

FAAT – Fully Analytical Aerotriangulation

FAC – Feature analysis code(s)

FACC Feature and Attribute Coding Catalog

FBX MER (Land Status Records) – Fairbanks Meridian.

FC (Land Status Records) – Final Certificate.

FED (Land Status Records) – Federal.

FED – Federal. If shown as a citation [198 Fed. 125 (1912)], it means “Federal Reporter.”

FF LSE (Land Status Records) – Fur farm lease.

FFMC (Land Status Records) – Federal Farm Mortgage Corporation.

FHA (Land Status Records) – Farmers Home Administration.

FIS (Land Status Records) – Fissionable materials.

FL – Florida.

FLA. – Florida.

FLPMA – Federal Land Policy and Management Act, of 1976.

FLS (Land Status Records) – Forest lieu selection.

FLUP – Free land use permit.

FM U (Land Status Records) – Farm unit.

FPA (Land Status Records) – Federal Power Act.

FPAS ACT – The Federal Property and Administration Services Act of 1949, as amended, sets forth the basic
contracting procedures and principles which all civilian agencies must follow.

FPC (Land Status Records) – Federal Power Commission.

FPR – Federal Procurement Regulations.

FR (Land Status Records) – Federal Register.

FRAC (Land Status Records) – Fractional.

FRAC INT PAT (Land Status Records) – Fractional Interest patent.

FS (Land Status Records) – Forest Service.

F. SUPP. – Federal Supplement.

FUP (Land Status Records) – Free use permit.

F&WS (Land Status Records) – Fish and Wildlife Service.

FX (Land Status Records) – Forest Exchange.

F STOP – A point on the scale of graduations of lens aperture size. The function of focal length is divided by the aperture of a lens.

FALSE COLOR – Reproduction that shows objects in colors other than their true color. Usually refers to color Infrared.

FALSE ORIGIN – An arbitrary zero point to the south and west of a grid zone that is assigned to avoid negative coordinate values.

FATHOM – 1) A unit of distance equivalent to 6 feet, used primarily in marine depth measurements. 2) To find the depth of something; to sound.

FEATHERING – 1) The technique of progressively dropping contours, to avoid congestion on steep slopes. 2) The
thinning of overlapping edges of photographs before assembly into a mosaic in order to make match lines less noticeable.

FERTSCH EFFECT – A phenomenon of physiological optics that occurs with rapid scanning of a stereo model in a
direction parallel to the eye base and that appears as a vertical displacement of the floating mark which reverses
with the direction of scanning. The effect is directly related to the relative brightness of the two exposures in the
immediate vicinity of observation, and to the fact that the human eye tends to detect the movement of the floating mark more quickly in a bright background than in a dark one.

Please feel free to contact us about Land Survey Terms or any other questions. We are here now and ready to answer.


FIDUCIAL AXES – The imaginary lines defined by opposite fiducial marks on a photograph. The x-axis is
considered to be the axis nearly parallel with the flight lines.

FIDUCIAL MARKS – Those marks, which define the axes whose intersection fixes the principal point of the
photograph. See FIDUCIAL AXES.

FIELD BOARD – Slang for plane table sheet. See preferred FIELD SHEET.

FIELD CHECK (USGS) – An on-the-site comparison of the features shown on a map compilation with the ground
features.

FIELD COMPLETION (USGS) – Obtaining in the field additional information needed to edit and publish a
topographic quadrangle map from a compiled manuscript. It includes a comprehensive examination of the
compilation for completeness, quality, and topographic expression; the addition, deletion, or correction of map
features; the classification of buildings, roads, drainage, and woodland; the mapping of public-land subdivision
lines and civil boundaries; obtaining name information; and checking the map for compliance with vertical-
accuracy standards.

FIELD CONTOURING – Placing contours on a topographic map by plane table surveys on a prepared base.

FIELD COPY – See preferred FIELD SHEET.

FIELD EDIT – See preferred FIELD COMPLETION.

FIELD ELEVATION – Any elevation determined by field methods.

FIELD INSPECTION – The process of comparing aerial photographs with conditions as they exist on the ground
and of obtaining information to supplement or clarify that which is not readily discernible on the photographs
themselves.

FIELD PHOTOINTERPRETATION – The operation of annotating aerial photographs in the field to clarify
uncertain photo images, to add details not discernible on the photographs, and to delete features appearing on
photographs not map-worthy or no longer present on the ground. See ADVANCE FIELD COMPLETION.

an image of a white circular Compass with Back Azimuth
FIELD POSITION (USGS) – 1) A position determined by fieldwork. 2) A position computed while fieldwork is in progress.

FIELD SHEET (USGS) – A sheet of stable material generally used on a plane table, either blank or with compiled data, on which fieldwork is plotted. Also called a plane table sheet. In field completion surveys, it contains the compilation to be completed.

FIELD SKETCHING (USGS) – The art of drawing or filling in map detail based on selected positions and
elevations plotted on a plane table sheet.

FILL – Use of material to equalize or to raise topography to a certain grade; to build up with fill; to fill the low ground with sand, gravel, or earth; the material used to artificially raise topography.

FILM BASE – A thin flexible transparent sheet of material used as a support for photographic emulsion.

FILM DISTORTION – The nonuniform dimensional changes which occur in photographic film with changes in humidity or temperature, or from aging, handling, or other causes. (Note: The failure of film to be flat in the camera at the instant of exposure is sometimes referred to, incorrectly, as film distortion. Although lack of flatness may result in errors on the photograph similar to those caused by film distortion, the cause of these errors is incomplete functioning of the pressure or vacuum system of the camera rather than dimensional instability of the film.)

FILM MOSAIC (USGS) – An assembly of film negatives or positives of a map manuscript adjusted and fitted to a
map projection constructed on a transparent base.

FILTER – 1) An electronic device for eliminating or reducing certain waves or frequencies while leaving others relatively unchanged. 2) Any material which modifies radiation transmitted through an optical system by absorption, reflectance, polarizing or scattering.

FIORD – A long, narrow inlet into the sea coast, with more or less steep sides.

FIRST ORDER – The designation is given survey work or equipment which conforms to the highest standards of
precision and accuracy. See CONTROL SURVEY CLASSIFICATION.

FIRST ORDER MAGNITUDE RELIEF FEATURE – A continent or an ocean basin.

FIRST ORDER PLOTTER – An obsolescent term originally designating a stereo instrument capable of performing aero triangulation.

FIXED – A descriptive term used with a benchmark, point, position, station, etc., to designate a point for which
geodetic coordinates (latitude and longitude, or elevation) have been established by a previous adjustment or by
a more precise survey and are to be held without disturbance in a newer survey or adjustment. See FIXED
BOUNDARY*.

FIXING – The process of rendering a developed photographic image permanent by chemically removing the
unaffected light-sensitive material.

FLAT – 1) A level surface, without elevation, relief, or prominences; a plain; a level tract along the banks of a river.
2) A level tract lying at little depth below the surface of the water, or alternately covered and left bare by the
tide. See OPTICAL FLAT.

FLATNESS OF FIELD – The quality of a lens that affords sharpness of image both in the center and at the edges
of a negative.

<span style=”font-family: arial, helvetica, sans-serif; font-size: 18px;”><span style=”color: #004fbd;”><img class=”alignleft wp-image-9816″ src=”https://haller-blanchard.com/wp-content/uploads/2021/12/the-safe-companies-contact-us.gif” alt=”” width=”38″ height=”38″ />Please feel free to</span> <a href=”https://haller-blanchard.com/contact-land-survey-company//”>contact us</a> <span style=”color: #004fbd;”>about Land Survey Terms or any other questions. </span></span><span style=”font-family: arial, helvetica, sans-serif; font-size: 18px;”><span style=”color: #004fbd;”>We are here now and ready to answer.</span>
</span>

FLICKER METHOD – The alternative projection of corresponding photographic images onto a tracing-table
platen or projection screen, or into the optical train of a photogrammetric instrument. See STEREO IMAGE
ALTERNATOR.

FLIGHT ALTITUDE – The vertical distance above sea level of an aircraft in flight. In aerial navigation practice,
the altitude of an aircraft is always stated in relation to the sea level. See FLIGHT HEIGHT.

FLIGHT HEIGHT (OR FLYING HEIGHT) – The vertical distance between an aircraft in flight and the mean
the ground level of the area being photographed.

FLIGHT HEIGHT TO CONTOUR INTERVAL RATIO – See C FACTOR.

FLIGHT LINE – A line drawn on a map or chart to represent the planned or actual track of an aircraft.

FLIGHT MAP – A map on which are indicated the desired flight lines and (or) the positions of exposure stations
before aerial photographs are taken, or a map on which are plotted, after photography, selected air stations and
the tracks between them.

FLIGHT SPACING – The distance between adjacent tracks in a series of parallel aircraft flights.

FLIGHT STRIP – A succession of overlapping aerial photographs taken along a single course.

FLOATING MARK – A mark is seen as occupying a position in the three-dimensional space formed by the
stereoscopic fusion of a pair of photographs and used as a reference mark in examining or measuring the
stereoscopic model. The mark may be formed (1) by a real mark lying in the projected object space, (2) by two
real marks lying in the projected or virtually projected object spaces of the two photographs, (3) by two real
marks lying in the planes of the photographs themselves, and (4) by two virtual marks lying in the image planes
of the binocular viewing apparatus.

Please feel free to contact us about Land Survey Terms or any other questions. We are here now and ready to answer.

FLOOD-PLAIN – A plain, bordering a river, which has been formed from deposits of sediment carried down by the
river. When a river rises and overflows its banks, the water spreads over the floodplain; a layer of sediment is
deposited at each flood so that the floodplain gradually rises.

FLY LEVELING – Spirit leveling in which some of the restrictions of precise leveling, such as limiting lengths of
sights and balancing backsight and foresight distances are relaxed to obtain elevations of moderate accuracy
more rapidly.

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 ”equivalent” or “calibrated” to have a precise meaning. See BACK
FOCAL LENGTH, CALIBRATED FOCAL LENGTH, EFFECTIVE FOCAL LENGTH, EQUIVALENT

FOCAL LENGTH and NORMAL FOCAL LENGTH.

FOCAL PLANE – The plane perpendicular to the optical axis of the lens in which images of points in the object
field is focused.

FOCUS – The point toward which rays of light converge to form an image after passing through a lens or reflecting
from a mirror. Also defined as the condition of the sharpest imagery. See DEPTH OF FOCUS.

FOOT-METER ROD (USGS) – A stadia rod graduated in feet on one side and in meters on the other.

FOOT PLATE – A metal plate with a knob used as a turning point in leveling across the sand.

FORESIGHT – 1) A sight on a new survey point in connection with a survey, or on a previously established point
to close a circuit. 2) In leveling, a reading on a rod is held on a point to determine its elevation. See SIDE SHOT
and FORESIGHT*.

FORMAT – 1) The dimensions of the negative area within the focal-plane frame of the camera. 2) The dimensions
of a map.

FORMAT CENTER – The point near the center of a photograph at the intersection of the lines between fiducial
marks.

FORM LINES – Lines resembling contour lines, drawn to represent the shape of the terrain but without regard to
true vertical datum or regular spacing.

FOUND CORNER – A term adopted by the U.S. Geologic Survey for an existent corner of the Public Lands
Surveys which have been recovered by field investigation. See CORNER*.

FRACTIONAL SCALE – A map scale expressed as a fraction, as 1/24,000. See REPRESENTATIVE
FRACTION.

FREQUENCY – Number of repetitions of a periodic process per unit of time.

FUSION – That metal process that combines the two perspective images on the retinas of the eyes in such a manner as to give a mental impression of the three-dimensional model.

Please feel free to contact us about Land Survey Terms or any other questions. We are here now and ready to answer.

Here is a good source for becoming a Surveyor or learning about the industry to make certain it’s the right path for your future