Georeferencing is the process of assigning locations to geographical objects within a geographic frame of reference. It is fundamental to geospatial technologies in general, and geographic information system (GIS) in particular. Georeferencing means that the internal coordinate system of a digital map or aerial photo can be related to a ground system of geographic coordinates. A georeferenced digital map or image has been tied to a known Earth coordinate system, so users can determine where every point on the map or aerial photo is located on the Earth’s surface.

Geo-referencing means that the internal coordinate system of a map or aerial photo image can be related to a ground system of geographic coordinates. The toposheet is added in QGIS by layer toolbar in QGIS database as raster data set and then with the help of geo-referencer tool available in raster menu the image is added for geo-referencing. Control points are added by providing longitudes and latitudes of points as X and Y values respectively, Ground control points table is viewed and error is noted down.