Instead of georeferencing the image and deforming it, I'm trying to find the projection used by the author of the image.
I've got tens of these distribution maps to digitize. The idea is to avoid image distorsions and to find only the parameters of pixel dimension and top-left corner coordinates to move maps in the correct position. To do that I need the original coordinate system.
I used ArcGis 10.2.1 to compare and customize different coordinate systems, but no one matched and the variable parameters for every projection were few. I used Flex Projector, but it's not possible to import and overlap an image for a comparison, moreover the software exports many parameters I cannot use in a desktop GIS. Using EPSG codes in Qgis would take me months to find the proper one.
Any ideas how to solve it? or which GCS could fit better?