I need to open an OSM map, view it offline and then add POIs and straight lines between those POIs. Any idea on how to do it? I thought of Travelling Salesman but you can’t add straight lines and JOSM, but the only lines are streets and it’s not a good program to view maps. Any ideas? I guess I could use JOSM and model the lines between points as streets/paths.
I’d suggest something like Quantum GIS and add an additional vector layer. I’m intrigued by what you mean by a straight line: do you mean great circle lines, a rhumb line, or straight lines on a particular projection such as OSGB? It seems to me that you will need to think about which projection to use.