We just launched the first version of Navigation info. A more than useful totally free application to be able to see relevant information, on top of your favorite GPS navigator that is displayed on small floating screens.
You can visualize an altimeter, the current speed at which you are going and (this is in beta version, but it already offers quite reliable results) the speed limit of the road you are currently driving.
Now you can open for example google maps, launch navigation info, and automatically 3 floating windows will appear. You can adjust the size and colors of the altimeter and speedometer and the size of the speed limit and if you want to warn when exceeding X km / h or m / h the maximum allowed by the way.
You can also adjust the unit of measurement of the three viewers to km / h or miles / h
The speed limit is obtained from OpenStreetMap and all the limits of all the published routes are not (nor much less), but the main ones are.
You can enter yourself at www.openstreetmaps.com and edit the map and add speed limits of the areas that interest you most and Navigation info will notify you of the new speed you have added.
Note: Speed limit information is for information purposes, you should never take into account this information about the real one indicated by the road.
You can download the free android application from here: Navigation info – Altimeter, speedometer and speed limit on maps.