QGIS is a free, open-source, cross-platform Geographic Information System (GIS) application that enables users to visualize, edit, and analyze geospatial data. It supports a wide range of vector, raster, mesh, and point cloud formats, integrating seamlessly with tools like PostGIS, GRASS GIS, and GDAL. QGIS offers advanced cartographic capabilities, geoprocessing tools, and a robust plugin architecture, making it suitable for applications in agriculture, urban planning, environmental monitoring, and more.