GIS File Formats & Their Extensions

GIS File Formats & Their Extensions A Complete Reference Guide for GIS Professionals

 Geographic Information Systems (GIS) use different file formats to store spatial and attribute data. Understanding these formats is essential for GIS professionals, data engineers, and analysts. Below is a structured reference guide to the most common GIS file types and their extensions.

 

01. Shapefile (Vector Format)

Shapefile is one of the most widely used GIS formats, developed by Esri. It is important to note that a shapefile is not a single file it is a collection of files that must be kept together.  Required Files Extension Purpose .shp Stores geometry (points, lines, polygons) .shx Shape index file — links geometry to attributes .dbf Attribute table stored in dBase format  Optional Files Extension Purpose .prj Projection / coordinate system information .sbn / .sbx Spatial index files for faster queries .xml Metadata .cpg Character encoding specification   ⚠ Limitation: One shapefile can store only one feature class. Field names are limited to 10 characters and file size is capped at 2GB.

  

02. File Geodatabase (.gdb)

A File Geodatabase is an Esri proprietary format stored as a folder on disk. It overcomes many of the limitations of the Shapefile format. Extension:  .gdb  (folder structure, not a single file)  Can store: •        Multiple feature classes •        Feature datasets •        Raster datasets •        Tables and relationship classes •        Domains and subtypes Advantage Detail Large dataset support Up to 1TB per dataset, no 2GB file limit Better performance Faster queries with built-in spatial indexing Topology & networks Supports topology rules and network datasets Domains & subtypes Enforces data integrity at the schema level

 

03. Enterprise Geodatabase (SDE)

Enterprise Geodatabases are used in multi-user enterprise environments where many editors need to work on the same data simultaneously.  Connection file:  .sde  Supported backend databases: •        SQL Server •        Oracle •        PostgreSQL  Key capabilities: Feature Description Multi-user editing Multiple editors simultaneously with conflict detection Versioning Create and manage named versions of data Utility Network Supports ArcGIS Utility Network for infrastructure management Enterprise scale Designed for large organisations and complex workflows

 

04. GeoJSON

GeoJSON is an open standard format based on JSON for encoding geographic data structures. It is lightweight and ideal for web GIS applications.  Extensions:  .geojson  or .json  Supports: •        Points, lines, and polygons •        Feature collections with attributes •        Coordinate Reference System definitions  Popular platforms: •        ArcGIS Online •        Leaflet and Mapbox •        GitHub (renders GeoJSON on map automatically) •        REST APIs and web services

 

05. KML / KMZ (Google Earth)

KML (Keyhole Markup Language) is an XML-based format originally developed for Google Earth. KMZ is the compressed, zipped version of a KML file.  Extension Description .kml Keyhole Markup Language — plain XML text file .kmz Compressed (zipped) KML — smaller file size for sharing  Commonly used for: •        Google Earth visualisation •        Sharing simple geographic data with non-GIS users •        Field data collection exports •        Web-based map sharing

 

06. CAD Files

CAD files are commonly used in engineering, utilities, and infrastructure projects. GIS professionals frequently need to read or convert these formats.  Extension Software / Format .dgn MicroStation design file .dwg AutoCAD drawing file — most common CAD format .dxf Drawing Exchange Format — open CAD interchange format   💡 FME Tip: FME Desktop can read all three CAD formats directly and convert them to GIS formats such as File Geodatabase or Shapefile with full geometry and attribute mapping.

 

07. Raster Formats

Raster formats store geographic data as a grid of cells (pixels), each with a value. They are used for satellite imagery, elevation models, and continuous surface data.   Extension Format & Use .tif GeoTIFF — most widely used raster format, supports georeferencing .img ERDAS IMAGINE — used in remote sensing and image analysis .sid MrSID — multi-resolution compressed imagery .jp2 JPEG 2000 — compressed imagery with good quality retention .asc ASCII Grid — plain text raster, used for DEM and elevation data .ecw Enhanced Compression Wavelet — high compression, large imagery .cog (.tif) Cloud Optimized GeoTIFF — HTTP range request streaming    Cloud Optimized GeoTIFF (COG) A COG is a standard GeoTIFF with an internal structure that enables efficient HTTP range requests. This means cloud platforms can read only the portion of the file needed — without downloading the entire file. ✔     Used in AWS S3, Azure Blob Storage, Google Cloud Storage ✔     Supported by GDAL, ArcGIS, QGIS, and FME ✔     The preferred raster format for modern cloud-native GIS workflows Common applications: •        Satellite and aerial imagery •        Digital Elevation Models (DEM) •        Land use and land cover analysis •        Hillshade and terrain visualisation

 

08. LiDAR & Point Cloud Formats

LiDAR (Light Detection and Ranging) formats store 3D point cloud data captured by airborne or ground-based laser scanners. Used in elevation modelling, urban mapping, and infrastructure inspection. Extension Format & Description .las LAS — industry standard binary format for LiDAR point cloud data .laz LAZ — compressed LAS file (up to 85% smaller), open source .copc (.laz) Cloud Optimized Point Cloud — LAZ with streaming index for cloud access .e57 E57 — open standard for 3D imaging data from terrestrial scanners .pts PTS — plain text point cloud format (ASCII) .xyz XYZ — plain text X Y Z coordinate file   LAS vs LAZ — which to use? Format Characteristic LAS Full-size binary —fast to read, large file size LAZ Compressed LAS — same data, ~85% smaller, slightly slower to decompress COPC Cloud-native LAZ — enables direct streaming from cloud storage  Common applications: •        Digital Terrain Models (DTM) and Digital Surface Models (DSM) •        Urban 3D building and infrastructure modelling •        Flood risk and watershed analysis •        Utility corridor and vegetation encroachment surveys •        Autonomous vehicle mapping and navigation

 

09. ArcGIS Project & Layer Files

These are Esri-specific files that store project settings, layer definitions, and toolbox configurations — not the spatial data itself.  Extension Description .aprx ArcGIS Pro project file — stores maps, layouts, connections .mxd ArcMap document — legacy project file (ArcMap only) .lyrx ArcGIS Pro layer file — stores layer symbology and source path .lyr ArcMap layer file — legacy layer definition (ArcMap only) .tbx ArcMap toolbox — custom geoprocessing tools .atbx ArcGIS Pro toolbox — modern toolbox format .fme FME workspace — stores FME translation workflows .ffs FME Feature Store — cached FME feature data

 

10. Database & Portable Formats

These formats store spatial data within database containers, offering varying levels of portability and multi-user support.  Extension Database / Format .mdb Personal Geodatabase — legacy Access-based format (Esri, deprecated) .sqlite SQLite database — lightweight, file-based relational database .gpkg GeoPackage — open standard SQLite-based spatial container   Why GeoPackage (.gpkg) is gaining popularity: ✔     Open standard — not vendor-locked ✔     Stores multiple vector and raster layers in a single file ✔     Portable and lightweight — ideal for field workflows ✔     Supported by QGIS, ArcGIS, GDAL, and FME

 

11. Scientific & Big Data Formats

These formats are used in climate science, oceanography, remote sensing, and large-scale analytics platforms. Increasingly relevant as GIS merges with big data pipelines.  Extension Format & Use .nc NetCDF — multidimensional scientific data (climate, atmosphere, ocean) .hdf / .h5 HDF5 — hierarchical data format for large scientific arrays .parquet GeoParquet — columnar format for large-scale vector data in cloud/data lakes .csv CSV — plain text tabular data with lat/lon columns for point data .grib GRIB — meteorological and climate model data (WMO standard) .zarr Zarr — chunked, compressed, cloud-native array storage   GeoParquet is emerging as the standard for sharing large vector datasets in cloud environments (AWS, Azure, GCP) because it is columnar, compressed, and supports spatial indexing natively.

 

Master Quick Reference

Extension(s)	Format & Use
.shp / .dbf / .shx	Shapefile — vector, single feature class
.gdb	File Geodatabase — multi-layer, Esri format
.sde	Enterprise Geodatabase connection file
.geojson / .json	GeoJSON — open standard, web GIS
.kml / .kmz	KML/KMZ — Google Earth format
.dwg / .dgn / .dxf	CAD files — engineering/infrastructure
.tif / .img / .asc	Raster imagery and elevation data
.aprx / .mxd	ArcGIS project files
.lyrx / .lyr	Layer files — symbology and source definitions
.gpkg	GeoPackage — open, portable, multi-layer
.fme	FME workspace file
.prj	Projection / coordinate system definition

 

Final Thought Understanding GIS file formats helps with: •        Data exchange across platforms and organisations •        Performance optimisation for large datasets •        Enterprise architecture design and platform decisions •        Avoiding compatibility issues in production workflows   Choosing the right format depends on: Requirement Recommended Format Data size Use File Geodatabase or Enterprise GDB for large datasets Editing needs Shapefile for simple; GDB for schema-rich environments Multi-user access Enterprise Geodatabase (SDE) for concurrent editing Web integration GeoJSON for web GIS; KML for Google Earth sharing Portability GeoPackage (.gpkg) for single-file, cross-platform portability