This tutorial is about Georeferencing, which is the first step in our Introduction to GIS series. GIS means “Geographic Information System.” Georeferencing is a very technical activity but we are going to focus on the practical elements that will allow you complete the georeferencing task on a scanned image of a map. 

Georeferencing, in the most simplistic terms, is layering a scanned map (likely a print map that has been scanned and saved as an image file or a pdf file) on top of a satellite map and locating reference points (known as “Ground Control Points”) on both maps in order to align the scanned map accurately with the satellite map. By using as little as three of these Ground Control Points, you can begin to locate the scanned map on the satellite map, which is the first step to creating and embedding geographic data to that map for comparison and analysis.