Land Survey Terms & Abbreviations: A Plain-English Glossary

A survey drawing, a recorded plat, or an Elevation Certificate can be hard to read the first time you see one. Land survey terminology mixes short abbreviations, historic units of measurement, and terms from property records and flood mapping.

This glossary explains the land survey terms and abbreviations that property owners in {{CITY}} see most often, in plain English. Where it helps, a term links to the survey service it relates to.

Abbreviations vary by surveyor and region. Every survey drawing should include a legend or notes that explain its abbreviations and symbols. If the legend on your survey defines a term differently than this list, the legend on your survey is the one that applies.

Common Abbreviations on a Survey Plat

These abbreviations appear in the legend, the notes, and next to the corners and lines of a survey or plat. Many marker abbreviations end in F for found, an existing marker the surveyor located, or S for set, a new marker the surveyor placed.

POB (Point of Beginning)

The starting point of a metes and bounds description. The description runs from the POB around the property and returns to it, which closes the boundary.

POC (Point of Commencement)

A known point, such as a section corner or a monument at a street intersection, that a legal description starts from when the property corner itself is not a known point. The description runs from the POC to the POB.

IPF (Iron Pipe Found)

An existing iron pipe marker the surveyor located. On some plats, IPF stands for iron pin found.

IPS (Iron Pipe Set)

A new iron pipe marker the surveyor placed. On some plats, IPS stands for iron pin set.

IRF (Iron Rod Found)

An existing iron rod, often rebar, that the surveyor located at a corner. The note may add the rod size and the stamp on its cap, such as a surveyor's license number.

IRS (Iron Rod Set)

A new iron rod the surveyor placed, usually with a plastic or aluminum cap stamped with the surveyor's license number or firm name.

CM (Concrete Monument)

A concrete post set at a corner, often with a metal disk, a rod, or a cut mark at the center that identifies the exact point. Concrete monuments are common at subdivision corners and along street lines. See what survey markers look like.

PK Nail

A hardened survey nail driven into asphalt or concrete to mark a point where a rod cannot be set, such as in a driveway or parking lot. The name comes from the Parker-Kalon brand. A MAG nail is a similar magnetic survey nail.

BM (Benchmark)

A stable, marked point with a known elevation. Surveyors measure elevations from a benchmark, and the survey notes name the benchmark and the vertical datum used.

ROW or R/W (Right-of-Way)

A strip of land used for a road, railroad, or utility line. It may be owned by a public agency or held as an easement. The right-of-way line is often set back from the edge of the pavement, so part of a front yard can fall inside the right-of-way.

N/F (Now or Formerly)

Placed before the name of an adjoining owner taken from the public records. It signals that the neighboring property may have changed hands since that record.

ESMT (Easement)

Marks an easement on the drawing, usually with its width, its purpose, and the reference to the recorded document that created it.

U.E. (Utility Easement)

An area set aside for utility lines such as power, water, sewer, gas, or communications.

P.U.E. (Public Utility Easement)

A utility easement dedicated for use by public utility providers, often along the front or rear lines of lots in a subdivision.

D.E. (Drainage Easement)

An area reserved for stormwater drainage, such as a swale, ditch, or pipe. Fences, sheds, and fill in a drainage easement can be restricted by the terms of the easement.

BSL (Building Setback Line)

The line that buildings must stay behind, measured from a property line or street. It may come from zoning, the recorded plat, or deed restrictions. Some plats use BRL, for building restriction line.

C/L (Centerline)

The center of a road, right-of-way, or easement. The width of an easement or right-of-way is sometimes described as a distance on each side of the centerline.

Boundary and Legal Description Terms

Metes and bounds

A way of describing land by its boundary. The metes are the measurements of each line, its bearing and distance. The bounds are references to monuments, natural features, roads, or adjoining properties. The description starts at the POB and follows each line around the property back to it. It is common for rural land and older parcels.

Lot and block

A way of describing land by reference to a recorded subdivision plat, such as Lot 5, Block 2 of a named subdivision. The plat holds the dimensions, so the deed does not need to repeat them.

Bearing

The direction of a line, written as an angle measured east or west from north or south, such as N 45°30'15" E. Each survey states its basis of bearings, the line or system its bearings are measured from, so two surveys of the same line can show slightly different bearings.

Call

Each element of a legal description: a bearing, a distance, a monument, or an adjoining property line. When calls conflict, for example when a distance does not reach the monument it calls for, the surveyor weighs the evidence. Under the general rules surveyors and courts apply, a monument called for in a deed usually carries more weight than a measurement.

Monument

A physical marker that identifies a boundary corner or a survey point. Artificial monuments include iron rods, iron pipes, and concrete monuments. Natural monuments, such as a tree, a stream, or a large rock, appear in many older deeds. Our guide on how to find your property lines shows the common types.

Encroachment

An improvement, such as a fence, driveway, shed, or building, that extends over a property line, into an easement, or past a setback line. A boundary survey shows the visible encroachments the surveyor finds.

Easement

A right for someone other than the owner to use part of a property for a specific purpose, such as utilities, drainage, or access. The owner keeps ownership of the land. Recorded easements are usually listed in the title commitment, and a lot survey shows the recorded easements that affect the property.

Setback

The minimum distance a building or other structure must be from a property line, a street, or another feature. Setbacks come from zoning codes, the recorded plat, deed restrictions, or HOA rules, and they can differ for front, side, and rear lines. The local permit office in {{CITY}} can tell you which setbacks apply to your property.

Plat

A scaled map of land. A subdivision plat divides a tract into lots, blocks, streets, and easements and is recorded with the county. A plat of survey, or survey plat, is the drawing of one specific survey. It shows the boundary, the monuments, the bearings and distances, and the improvements on the property.

Plat book

The county record where recorded plats are kept. A deed or survey often cites a plat by book and page number, or by another recording reference. In {{COUNTY}} County, plats are recorded with the county office that records deeds and plats.

Elevation and Flood Terms

These terms appear on FEMA flood maps, Elevation Certificates, and topographic surveys.

BFE (Base Flood Elevation)

The elevation floodwater is expected to reach in the base flood, a flood that has a 1% chance of being equaled or exceeded in any given year. The base flood is often called the 100-year flood. Flood maps show BFEs for many high-risk zones, and an Elevation Certificate compares a building's elevations with the BFE.

LAG (Lowest Adjacent Grade)

The lowest elevation of the finished ground next to a building's exterior walls. It is one of the measurements recorded on an Elevation Certificate.

HAG (Highest Adjacent Grade)

The highest elevation of the finished ground next to a building's exterior walls. It is also recorded on an Elevation Certificate.

FFE (Finished Floor Elevation)

The elevation of the top of a finished floor, usually the lowest floor of a building. Site plans and permits often specify an FFE. In flood zones, local rules may require the lowest floor to be at or above the BFE, sometimes with extra height called freeboard.

SFHA (Special Flood Hazard Area)

The area that FEMA maps as subject to flooding in the base flood. On a flood map, SFHAs are the zones that begin with A or V. Lenders generally require flood insurance for buildings in an SFHA that have a federally backed mortgage.

FIRM (Flood Insurance Rate Map)

The official FEMA flood map for a community. It shows the SFHAs, the BFEs, and the flood zones used for flood insurance and floodplain management. Current maps are available from FEMA's Flood Map Service Center.

LOMA (Letter of Map Amendment)

An official letter from FEMA that amends the flood map for a property or structure that the map shows in an SFHA but that sits on natural ground at or above the BFE. A LOMA can remove the federal flood insurance requirement, though a lender may still require coverage. The request needs elevation information, which is usually certified by a licensed land surveyor or engineer. Where the ground was raised with fill, the request is a LOMR-F, a Letter of Map Revision based on Fill.

NAVD 88 (North American Vertical Datum of 1988)

The official vertical datum for the conterminous United States and Alaska: the reference that elevations are measured from. It replaced NGVD 29, and newer FEMA flood maps generally use it.

NGVD 29 (National Geodetic Vertical Datum of 1929)

The earlier national vertical datum, replaced by NAVD 88. Older flood maps, plans, and benchmarks may still use it. The difference between the two datums varies by location, so a surveyor converts elevations from one to the other instead of mixing them.

Datum

A reference system that positions or elevations are measured from. A horizontal datum, such as NAD 83, is used for positions, and a vertical datum, such as NAVD 88, is used for elevations. A survey notes the datums it uses, because elevations on different datums cannot be compared directly.

Contour interval

The vertical distance between neighboring contour lines on a topographic map. With a 1-foot contour interval, each line is 1 foot higher or lower than the next. A smaller interval shows more detail. A topographic survey states the contour interval it uses.

Land Survey Units of Measurement

Modern surveys use feet or meters, but older deeds and plats often use historic units. Surveyors convert them when they retrace an older description.

Chain

A unit of length equal to 66 feet, from the measuring chain that Edmund Gunter introduced in 1620, often called Gunter's chain. Eighty chains make a mile, and 10 square chains make an acre.

Link

One hundredth of a chain, or 7.92 inches. Older deeds often give distances in chains and links, such as 4 chains 25 links.

Rod, pole, or perch

Three names for the same unit of length: 16.5 feet, or one quarter of a chain.

Acre

A unit of area equal to 43,560 square feet, or 10 square chains. An acre has no fixed shape. There are 640 acres in a square mile.

Vara

A Spanish unit of length found in land records from areas once under Spanish or Mexican rule. In Texas, state law fixes the vara at exactly 33 1/3 inches. Its length varied in other places, so a surveyor confirms which value applies to an old description.

U.S. survey foot

The foot long used for land surveying in the United States. It differs from the international foot, exactly 0.3048 meter, by about 2 parts per million. NIST and NOAA retired it in favor of the international foot at the start of 2023, but it still appears in older records and coordinates, so surveyors check which foot a document uses.

Surveyor Credentials and Standards

State law regulates the practice of land surveying, and each state's licensing board sets the title its surveyors use. Whatever the title, the final survey is signed and sealed by the licensed surveyor responsible for it, as state rules require.

In {{STATE}}, land surveyors are licensed with the title {{LICENSE_TITLE}}. You can verify a surveyor's license with the {{LICENSE_BOARD_NAME}} ({{LICENSE_BOARD_URL}}).

PLS (Professional Land Surveyor)

A license title used in many states for a land surveyor licensed by the state.

RLS (Registered Land Surveyor)

A license title some states have used, and one you may see on older surveys.

RPLS (Registered Professional Land Surveyor)

The license title used in Texas.

PSM (Professional Surveyor and Mapper)

A license title used where state law licenses surveying and mapping as one profession.

ALTA/NSPS

The Minimum Standard Detail Requirements for ALTA/NSPS Land Title Surveys: the national standards for land title surveys used in commercial real estate, written jointly by the American Land Title Association (ALTA) and the National Society of Professional Surveyors (NSPS). The current standards took effect on February 23, 2026. Editions before 2016 were called the ALTA/ACSM standards. Learn more about an ALTA/NSPS land title survey.

Table A

The list of optional items in the ALTA/NSPS standards that a client, lender, or title company can add to a survey, such as monuments, flood zone classification, zoning setbacks, building dimensions, parking, and evidence of underground utilities. The 2026 standards list 20 numbered optional items, and item 21 covers other items negotiated for the project.

NSPS (National Society of Professional Surveyors)

A national professional organization for surveyors in the United States. It writes the ALTA/NSPS standards together with the American Land Title Association.

Surveying Technology Terms

GNSS (Global Navigation Satellite System)

The general term for satellite positioning systems, including GPS (United States), GLONASS (Russia), Galileo (European Union), and BeiDou (China). Survey-grade receivers can track signals from several systems at once.

RTK (Real-Time Kinematic)

A GNSS method that uses corrections from a nearby base station or a correction network to compute positions to within a few centimeters, in the field and in real time. A phone's GPS is typically accurate only to several meters.

Total station

An electronic instrument that measures horizontal and vertical angles and the distance to a target to locate points precisely. Surveyors use total stations for boundary work, construction staking, and places where trees or buildings block satellite signals.

LiDAR (Light Detection and Ranging)

A sensor that sends out laser pulses and times their return to measure distances, building a dense 3D point cloud. Mounted on a drone, an aircraft, a vehicle, or a tripod, LiDAR can often reach the ground through gaps in tree cover. See drone LiDAR mapping.

Photogrammetry

Measuring from overlapping photographs. Software processes drone or aerial images into orthomosaics (scaled, corrected aerial maps), surface models, and point clouds. Ground control points measured by the surveyor tie the results to survey coordinates.

As-built

A survey made after construction that shows the location and elevation of what was actually built, such as a foundation, a building, utilities, or grading, so it can be compared with the approved plans. As-built surveys are part of construction surveying.

Need a Land Survey in {{CITY}}?

A glossary helps you read a survey, but it cannot tell you what your survey means for your property. If a corner marker is missing, a line does not match the fence, or a note on the plat is unclear, a licensed surveyor can review the records and the ground and explain the findings.

To get started, gather what you have: your property address or parcel ID, your deed, any earlier survey, plat, or Elevation Certificate, the reason for the survey, and any deadline. Those details let us scope the work and give you an accurate quote.