Open-source ArcGIS alternatives

QGIS is a full-featured, user-friendly and free-and-open-source geographic information system that runs on Unix platforms, Windows and macOS. It is written in C++ and licensed under GPL-2.0, and it is used to manage, map and analyze spatial data.

It supports raster, vector, mesh and point cloud data in many standard formats, including GeoPackage, GeoTIFF, shapefiles, PostGIS, WFS, NetCDF and LAS/LAZ. A data abstraction framework presents local files, spatial databases such as PostGIS, SpatiaLite, SQL Server and Oracle, and web services such as WMS, WCS and WFS through one data model. Users can digitize and edit data, georeference rasters and vectors, reproject coordinate systems on the fly, and use a Nominatim geocoder.

Further areas covered in the README include cartography with a large variety of rendering options, temporal support and 3D map views, geospatial analysis, customization and extensibility, and QGIS Server for publishing maps over the web. The project follows a versioned release cycle and offers documentation, support channels and community participation.

GeoServer is an open-source server written in Java that lets users share and edit geospatial data. It serves data from the common spatial data sources through open standards, which keeps it interoperable with other geospatial software.

GeoServer is the reference implementation of the Open Geospatial Consortium's Web Feature Service and Web Coverage Service standards, and offers a certified compliant Web Map Service. It also implements OGC API - Features, Catalog Service for the Web and Web Processing Service. Supported formats include GeoPackage and GeoTIFF as reference implementation, plus GML and Shapefile.

GeoServer is community-driven, developed and supported by individuals and organizations around the world, and is licensed under the GPL. It builds with Apache Maven, the user guide and developer guide explain installation and development, documentation is written in Markdown with MkDocs, and issues are tracked in JIRA.