GIS File Types and Formats

In Geographic Information Systems (GIS), data can come in various file formats, each serving different purposes and offering unique advantages. Understanding these formats is essential for effective GIS data management and analysis.

Vector Data Formats

Shapefile (.shp)

A popular vector format developed by Esri, used to store geometric location and attribute information of geographic features. Used for a variety of GIS applications, including mapping and spatial analysis.

Components

  • .shp: Stores the feature geometry.
  • .shx: Index file that links the geometry to the attributes.
  • .dbf: Attribute data in tabular form.
  • .prj: Projection information (optional but recommended).

Advantages:

  • Widely supported across various GIS platforms.
  • Simple and efficient for small to medium-sized datasets.

GeoJSON (.geojson)

A format based on JSON (JavaScript Object Notation) for encoding a variety of geographic data structures. Commonly used for web mapping and sharing geographic data via APIs.

Advantages:

  • Lightweight and easy to read and write.
  • Ideal for web applications due to its text-based nature.

KML/KMZ (.kml, .kmz)

Keyhole Markup Language (KML) is an XML-based format for representing geographic data for applications like Google Earth. KMZ is a compressed version of KML. Ideal for presenting geographic data to a broad audience and for creating interactive maps.

Advantages:

  • Easily shared and visualized in Google Earth.
  • Supports 3D visualization and rich annotation.

GML (.gml)

Geography Markup Language (GML) is an XML-based format for storing geographic data and metadata. Often used in governmental and large-scale data integration projects.

Advantages:

  • Highly flexible and capable of storing complex spatial and attribute data.
  • Widely used in data exchange standards and interoperability projects.

File Geodatabase (.gdb)

A database format developed by Esri for storing and managing GIS data. Commonly used in enterprise-level GIS projects and advanced spatial analyses.

Advantages:

  • Supports large datasets and complex data types.
  • Allows for advanced geoprocessing and analysis within the Esri ecosystem.

GeoPackage (.gpkg)

An open, standards-based format for vector and raster data that uses a SQLite database container. Ideal for mobile and embedded applications, as well as cross-platform data sharing and analysis.

Advantages:

  • Compact and efficient, storing multiple types of data in a single file.
  • Supports both vector and raster data.
  • Platform-independent and widely supported.

Raster Data Formats

GeoTIFF (.tif, .tiff)

A TIFF file with embedded geographic metadata, such as projection and coordinate system information. Used extensively in remote sensing, imagery, and elevation data.

Advantages:

  • Highly versatile and widely supported.
  • Can store large and high-resolution raster data.

NetCDF (.nc)

Network Common Data Form (NetCDF) is a set of software libraries and self-describing, machine-independent data formats for array-oriented scientific data. Ideal for storing and sharing large-scale environmental data and climate models.

Advantages:

  • Supports large multi-dimensional datasets.
  • Widely used in scientific research, particularly in climatology and oceanography.

Erdas Imagine (.img)

A format developed by Hexagon Geospatial for raster data. Preferred for complex raster analyses and large datasets in remote sensing.

Advantages:

  • Supports multiple bands and advanced raster data types.
  • Compatible with Erdas Imagine software, commonly used in remote sensing.

GRID

A raster format used by Esri's ArcGIS software for storing spatial data. Used for terrain modeling, land cover classification, and other raster analyses.

Advantages:

  • Efficient storage of raster data with support for spatial analysis.
  • Optimized for use within the ArcGIS environment.

3D File Types

LAS/LAZ (.las, .laz)

LAS is a standard format for LiDAR data. LAZ is its compressed version. Used for storing and sharing high-resolution 3D point cloud data captured by LiDAR sensors.

Advantages:

  • Efficient storage and management of large point cloud datasets.
  • Widely supported in LiDAR processing and analysis software.

PLY (.ply)

Polygon File Format or Stanford Triangle Format, used for storing 3D point cloud data. Commonly used in 3D scanning, modeling, and printing applications.

Advantages:

  • Supports both ASCII and binary encoding for flexibility and efficiency.
  • Contains detailed information about 3D structures.

OBJ (.obj)

A geometry definition file format for 3D models. Ideal for representing complex 3D models in GIS and CAD applications.

Advantages:

  • Supports both polygonal and freeform geometry (curves and surfaces).
  • Widely used for 3D graphics and modeling.

Attribute Data Formats

CSV (.csv)

Comma-Separated Values (CSV) is a simple format for tabular data. Frequently used for attribute tables, survey data, and data exchange.

Advantages:

  • Easy to create and read with any text editor or spreadsheet software.
  • Widely supported for importing and exporting attribute data.

Excel (.xls, .xlsx)

Spreadsheet format used by Microsoft Excel. Commonly used for attribute data management and reporting.

Advantages:

  • Supports complex data structures, formulas, and data visualization.
  • Easily shared and edited by non-GIS users.

Metadata Formats

XML Metadata (.xml)

XML format used to store metadata information about GIS datasets. Used for documenting GIS datasets to ensure proper data management and interoperability.

Advantages:

  • Ensures consistent documentation of data sources, quality, and usage.
  • Widely supported for metadata standards and data exchange.

ISO 19115 Metadata

An international standard for describing geographic information and services. Essential for large-scale and international data sharing projects.

Advantages:

  • Provides a comprehensive framework for metadata documentation.
  • Enhances data discovery and usability through standardized metadata.

Other GIS-Related File Formats

Layer File (.lyr, .lyrx)

Stores the path to a source dataset and the symbology and display properties. Used for saving and sharing map layer configurations in ArcGIS.

Advantages:

  • Allows for consistent visualization of geographic data across different projects.
  • Easy to share and apply standardized symbology.

Map Document (.mxd)

A file format used by Esri's ArcMap to save map layouts and settings. Essential for project documentation and sharing in ArcGIS.

Advantages:

  • Preserves map layouts, symbology, and settings for consistent map production.
  • Supports complex map compositions and analysis workflows.

ArcGIS Pro Project (.aprx)

The project file format used by Esri's ArcGIS Pro to organize and manage GIS data, maps, layouts, tasks, and tools. Used for comprehensive project management in ArcGIS Pro, suitable for complex and multi-faceted GIS projects.

Advantages:

  • Supports a more modern and integrated workflow compared to .mxd files.
  • Allows for the inclusion of multiple maps and layouts within a single project file.
  • Enhances project management with tasks and tools directly embedded.

SQLite/SpatiaLite (.sqlite)

A spatial extension of SQLite, a lightweight database format. Suitable for mobile and embedded GIS applications, as well as lightweight data management.

Advantages:

  • Combines the simplicity of SQLite with spatial data handling capabilities.
  • Portable and efficient for managing spatial data.