GIS Glossary
Your pocket dictionary for geospatial terminology. Learn the lingo and find the right tools for the job.
Buffer
A zone of a specified distance around a map feature (point, line, or polygon). Buffers are used in proximity analysis, such as "show all houses within 1 mile of this store".
CSV (Comma Separated Values)
A simple text file format used to store tabular data, like spreadsheets. GIS tools often use CSVs to store lists of coordinates (Latitude/Longitude).
DEM (Digital Elevation Model)
A 3D representation of a terrain's surface created from terrain elevation data. DEMs are often used to generate contours or hillshades.
DXF (Drawing Exchange Format)
A CAD data file format developed by Autodesk for enabling data interoperability between AutoCAD and other programs. Often needs conversion to be viewed on web maps.
Geocoding
The process of converting addresses (digital text) into geographic coordinates (latitude and longitude) that can be placed on a map.
GeoJSON
An open standard format designed for representing simple geographical features, along with their non-spatial attributes, using JavaScript Object Notation (JSON). It is the standard for web mapping.
GeoTIFF
A public domain metadata standard which allows georeferencing information to be embedded within a TIFF image file. Common for satellite imagery and drone maps.
GPX (GPS Exchange Format)
An XML schema designed as a common GPS data format for software applications. It can be used to describe waypoints, tracks, and routes.
KML (Keyhole Markup Language)
An XML notation for expressing geographic annotation and visualization within Internet-based, two-dimensional maps and three-dimensional Earth browsers. Native to Google Earth.
KMZ
A compressed (zipped) KML file. It may include a single KML file definition and zero or more supporting files, such as images/icons, packaged together.
Polygon
A plane figure that is bounded by a finite chain of straight line segments closing in a loop. In GIS, used to represent areas like lakes, property boundaries, or countries.
Raster
A spatial data model that defines space as an array of equally sized cells arranged in rows and columns (pixels). Examples include satellite imagery and elevation grids.
Reverse Geocoding
The process of converting geographic coordinates (latitude/longitude) into a human-readable address.
Shapefile (SHP)
A popular geospatial vector data format for geographic information system (GIS) software. Developed by Esri, it actually consists of multiple files (.shp, .shx, .dbf).
TMS (Tile Map Service)
A specification for tiled web maps, breaking large images into a pyramid of small 256x256 pixel image tiles for fast loading.
Vector
A data model that represents geographic features as points, lines, and polygons. KML, GeoJSON, and Shapefiles are all vector formats.
WGS84
World Geodetic System 1984. The standard coordinate system for the Earth, used by GPS and Google Earth. Referenced as EPSG:4326.