All the maps I get from the South African government mapping office, have been scanned in including all the very wide empty white space around the printed portion. When I drive off the edge of the printed portion, the crosshairs continue to move across the empty white border area until it reaches the end of the scanned paper sheet, then jumps onto the next map, but by then I am already quite deep into that new map, by the width of the empty white space around the edge of the previous map. Is there a way to set or mark map extents, so that as one get to the edge of the printed portion of the scanned paper map, it jumps directly onto the edge of the printed portion of the next map, without crossing so much white space?
Avenza Maps essentially detects the embedded referencing in the files which in this case, includes the white space around the maps. Although there is nothing there, the white space contains georeferencing so the extents of the georeferencing must be specified in the file prior to import. The only way to avoid this when scanning paper maps to digital would be to crop them in software like Geographic Imager for Adobe Photoshop. Unfortunately, in the app, there is nothing we can do at this time to prevent this another way.