QGIS

QGIS is the workhorse of open-source geospatial analysis — the free, community-maintained equivalent of ArcGIS. It handles raster and vector data, supports every common GIS format, and has a vast plugin library covering everything from georeferencing to network analysis to 3D visualisation. For Indian researchers and civic organisations, QGIS is essential: it lets you load government shapefiles (Survey of India, NWDP village boundaries), overlay them with satellite imagery (Sentinel, Landsat), join them with tabular data (Census, NFHS), and produce publication-quality maps. The interface is approachable for beginners but powerful enough for advanced spatial analysis. Runs on Windows, Mac, and Linux. The QGIS community maintains excellent documentation and tutorials in multiple languages.