This document provides an introduction to geographic information systems (GIS). It discusses key GIS concepts including geographic data, vector and raster data formats, georeferencing, queries, and geoprocessing tools. Geoprocessing involves operations to create new geographic datasets and includes conversion, overlay, extraction, proximity, management, transformation, and spatial analysis tools. The document is authored by Md. Yousuf Gazi, a lecturer in the Department of Geology at the University of Dhaka.