In reaction to my post Open Street Map for Overlanders (please have a look) Walkabout pointed me to this post.

I shared my experience with navigation systems on our website Navigation - De Einder Voorbij. The text is below. For images and links to the mentioned apps and digital map sources please visit the site.

Summary
Navigation consists of four elements:

• Hardware and associated software platform
• Maps
• Applications and programs
• Waypoints, tracks and routes

In addition of course there are the traditional paper maps.

Hardware and associated software platform
For navigation route we bought an Android tablet (we are not fans of Apple censorship ) that can be inserted above the windshield on the rack in a holder so that it is clearly visible during the trip. An additional advantage is that the holder does not look like a frame for expensive electronics ; that reduces the risk of burglary . For planning we use a PC with Windows 8 and for hiking and cycling , we use a (simple) Garmin eTrex 20 .

Maps
While reviewing maps we looked at countries like Sudan and Ethiopia. In comparison with for example Open Street Map (OSM ) and Microsoft Maps we found the maps from Google Maps the best. We made off-line maps at zoom level 12 (1: 150,000) for the countries and 17 (1: 4000 ) for the cities. Once underway the Google maps prove to be fine for Europe, Turkey, Iran and the Arabian Peninsula, but not so well in East Africa; OSM is better there.

Android Apps
On the tablet we used so far seven programs: OruxMaps (free), MapsWithMe Pro (almost free), Navigator ("turn- by-turn " navigation based on Open Street Map, free), OsmAnd+, Locus Pro and BRouter. We also purchased Tracks for Africa ( T4A ) the most often used navigation software for Southern Africa.

OruxMaps
OruxMaps is an excellent program to display maps and to capture and create routes. It accepts both online maps including Google Maps and OSM ( with cache) as offline cards. OruxMaps works with bitmaps and vector charts.

MapsWithMe
MapsWithMe works with vector OSM. This means that an entire country is defined at street level in a relatively small file. MapsWithMe constantly shows the current position on the detailed map and can store and display waypoints . It is more limited than OruxMaps, for example because it does not store the distance traveled and shows no height and speed

Navigator
Our experience with Navigator varies. The quality stands or falls with the quality of the OSM maps and varies somewhat per country. During our preparation trips it was fine in the Baltic countries and Scandinavia (better than a two year old TomTom ) but moderate in Morocco. We used Navigator seldom during the overland trip. Navigator works offline.

OsmAnd+
OsmAnd+ works with OSM only. The user interface is not very intuitive and it has few options, but it has all functionality needed: display of maps, route calculation (both native and BRouter), storage of favorite locations and searching of points of interest. Furthermore it is faster than OruxMaps or Locus Pro and has large buttons, making it easier to operate the device while driving.

Locus Pro
Locus Pro is comparable with OruxMaps. It is well designed, can display bitmaps as well as vector maps and can store tracks and favorite locations. However, it needs BRouter for navigation, is slow and harder to operate while driving.

BRouter
BRouter calculates routes based on the OSM database. It can only generate a .gpx file with the route, so always an additional app is needed for display and destination entry. OruxMaps, Locus Pro and OsmAnd+ all support it. It uses its own database, so if you use it in combination with for example OruxMaps you need two map databases: one for map display by OruxMaps and one for route calculation.

T4A
T4A used to be the holy grail for travelers in Africa, but we felt that OSM is as least as complete and up-to-date. The philosophy of both is that travelers collect data that is consolidated by an organization. He had some experiences that T4A had a POI that no other source had, but also that the information of T4A was outdated. We use it for POI locations only, not for turn-by-turn navigation. As its road database is incomplete this gives potentially strange results. Furthermore the application is slow and the user interface not friendly.

Conclusion
In Africa the OSM vector maps are the best source. The main application we use is OsmAnd+ despite its poor user interface and limited options. In critical situations we use both Brouter and native route calculation with it. We check both routes and add extra waypoints as needed to get the right road as both sometimes give strange results. T4A is an extra resource to find POIs such as campings.

PC-software
For map preparation and for processing of recorded tracks PCsoftware is needed.

OKMap
Editing routes on the PC we do with OkMap (free). Editing on the tablet with OruxMaps. OKMaps can also create maps for Garmin. Mixing traveled routes (a.o. for this site) we also do with OkMap .

MOBAC
OruxMaps used to be able to create offline maps from Google Maps, but that is no longer possible for licensing reasons. For route planning it can be useful to have the maps on the PC. We use MOBAC (Mobile Atlas Creator, free). The standard version does not accept Google Maps as input, but a simple .xml file can be found on the Internet to enable it.

Paper Maps
For route planning we use the famous Michelin maps of Africa and Middle East. For most countries we have completed the map set with maps at country level, mostly maps of "Reise Know- how". Electronics are nice, but to be safe we bring paper maps in addition: the Michelin maps for the Middle East , East Africa and Southern Africa as well maps from different publishers of the countries we pass.