The software „GROUPI for GPS“ can handle scanned maps with the file format *.jpg or *.gif. All maps with a standard scale can be used world wide. Usually you have a printed scale but it can also be calculated through calibration of the map.
The calibration of the maps is always necessary as you need coordinates of the route points within a system of coordinates available for your GPS receiver. For this reason you need so-called passpoints the coordinates of which have to be known to the user. There are two possibilities to get the coordinates of passpoints:
1.) You use maps with a printed coordinate grid. Each point of intersection on this grid can be used as passpoint. The coordinates are printed on the edge of the maps. Further details for this possibility see here.
2.) You use maps without coordinate grid (e.g. city maps often have no coordinate grid).Passpoints then can be main rectangular crossings. The adequate coordinates can be got free of charge and worldwide with help of the software “Google-Earth”. You find an instruction for using this software together with “GROUPI” here.
Parts of the maps can be scanned with all standard scanners. Scanners are available from DIN A4 to DIN A1. Should your journey area be more widespread as the scanner you can scan and deal with your map part by part.