Help with the olux map secret discovery

I found a map of olux swap that you need to fill in. I have found 3 of the 4 maps but cannot find the last one. Also it would be cool to know what its for. Thanks for any info about this.
imgur(.)com/a/JumFUFT

 

I don’t recall off the top of my head which maps slot where but they’re located: one behind the wall, two in front of the wall a few blocks away, and one in the tower in the orc camp across the road.