I'm looking at the following map and I can't figure out what kind of coordinate system is being used. This isn't lat/long. I assume once I know which coordinate system it is, I can easily search for a converter online.
As one can see, the coordinates are in the range of 784600N to 786000 N and 295800E to 297400E.
The area in question is Gabon. Around the lat/long coordinates of 1.69°S, 13.41°E