Michael didn't use Extraction on the maps spread all over the wooden desk. It might be easier to study the maps by extracting the knowledge wisps, but using Extraction on the maps would also erase the drawings. That was not something Michael wanted since he was sure that the maps would be useful in future warfares.
Hence, he studied the old fashioned way, trying to understand the vast terrain, topography and the distance of his territory from that of the other lords. While intently studying the maps for a second time, Michael learned lots of new things. He learned more about the Savannah region and the surrounding regions. Unfortunately, there weren't many detailed pieces of information about the surrounding regions. That was a shame, even if it didn't affect Michael too much. He wouldn't encounter anyone from the other territories anytime soon.
If anything, Michael was the most interested in the Savannah region since it was relatively close to his territory.