June 18, 2026
GPS Coordinates in Real Estate: Property Boundaries and Deed Descriptions
Property deeds, survey plats, and GIS parcel maps all use coordinates — but not always the same format. Here's what real estate professionals need to know.
GPS coordinates appear throughout real estate and property work — in survey plats, deed descriptions, GIS parcel data, and increasingly in property listing metadata. Understanding the formats prevents costly interpretation errors.
Deed Descriptions: DMS and Metes-and-Bounds
Traditional legal land descriptions use either metes-and-bounds (bearings and distances relative to a starting point) or Degrees Minutes Seconds for absolute corner coordinates. A deed might describe a boundary corner as "47°36′22.41″N 122°19′54.88″W." These coordinates must be interpreted precisely — a one-second error in a boundary coordinate can mean 30 metres on the ground.
Survey Plats and CAD Files
Modern survey plats are produced in CAD software (AutoCAD Civil 3D, Carlson) and typically output in State Plane Coordinates (a variation of UTM optimised for specific states) or in Decimal Degrees with a specified datum. GIS-ready plats use DD for easy import into ArcGIS or QGIS.
County GIS Parcel Data
Most US county assessors publish parcel data as GIS shapefiles with coordinates in WGS84 Decimal Degrees. This data powers services like Zillow, Redfin, and county parcel viewers. When you see a property boundary drawn on a map, it's almost certainly backed by DD coordinates.
Practical Workflows
When working with coordinates from mixed sources — a deed in DMS, GIS data in DD, survey control points in UTM — use our converter to normalise everything to a single format before analysis. Our DMS to DD guide is particularly useful for processing deed descriptions.
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