We have been exploring for over 2 years many properties in Latinamerica. The following have been the most reliable tools so far. Sometimes no Internet/3G (no coverage or too much demand). No GPS-Satellite (too many trees in the jungle). No Electricity to reload the batteries 🙂
It has been a real challenge to find good map-solutions with digital terrain elevation contour information. Same for our Garmin device witch operates with the free open source solution from OpenStreetMaps (OSM) http://wiki.openstreetmap.org Still trying to find a better information source here… more research is needed. Although I found another source of information regarding the How & Where to Find Free, Digital, Topographic Maps… here.
Best “Save GPS points” no need of Internet connection
smartphone app “MAPS.ME”
Best “Terrain” altitude info map (altitude information = elevation from sea level)
Google Maps – Terrain view
Best “Road” and “Terrain Contour” info
Best “River” info map
Yahoo / Flickr Map
Permaculture zone planning
Now for calculating the property sizes it’s not to complex to work with Google Earth / Pro and to do some permaculture zone planning for example. Actually Google Earth / Pro is rather straight forward to use, yet powerful interface, can be mastered in a few steps and provide you with a map you can print or share online. There is a great and detailed article about Using Google Earth to zone your farm is a great planning tool here so no need to re-write.