Georeferencing is the process of assigning spatial coordinates to raster data that has no geographic coordinate system (GCS) embedded in the file. Raster datasets are often aerial photographs, satellite images, or scanned maps which represent geographic features by dividing an image into a grid. Each cell of the grid has a value that is used to represent a characteristic of the location. Normally a scanned map won’t have a spatial reference until it is georeferenced.

This task sheet will guide you through georeferencing a historic map using the QGIS Georeferencing GDAL plugin.