I'm not a cartographer, but want to use a map for my project from world atlas book. I scanned the map, but no matter how carefully it is scanned, it's perspective is slightly distorted and it's noticeable because of longitude and latitude lines present. If I could tear the page, I can get desired result, but that's not an option.
Nice tool I use after scan is Scan Tailor which has "dewarp" function, that places grid on top of scanned image, and by defining and arranging arbitrary control points it can restore orthogonal transform of that grid. Here is image I found with Google, that can perhaps be more clear:
However I'm not satisfied with the result of this function, and can't seem to find any similar tool for the task. I expected to find Gimp plugin or standalone tool, but couldn't find it. I saw suggestion about panorama tool Hugin, but can't manage anything useful by myself.
So the question, is there any preferably free tool for Windows or Linux, that can let me define grid like in screenshot above and change it to orthogonal perspective?