In the tutorial Georeferencing Topo Sheets and Scanned Maps we covered the basic process of georeferencing in QGIS. That method involved reading the coordinates from your scanned map and inputting it manually. Many times though you may not have the coordinates printed on your map, or you are trying to georeference an image. In that case, you can use another georeferenced data source as your input. In this tutorial, you will learn how to use existing open data sources in your georeferencing process. We will georeference high resolution balloon-imagery using reference coordinates from OpenStreetMap. In this tutorial, we will be using some gorgeous kite and balloon imagery collected by The Public Laboratory. They make the georeferenced versions of the images also available, but we will download a non-georeferenced JPG image and go through the process of georeferencing it in QGIS. If you like the imagery they provide, you can explore it in Google Earth as well. Download the JPG image of Washington Square Park, New York. You can right-click the JPG button and choose Save link as…. Source.