Better prospecting map filter

[alexander corley]

When prospecting for specific materials (such as halite, magnetite, or coal), it’s useful to filter the prospected points on the map to show only those containing the desired ore. However, since the current filter completely removes points that lack the selected mineral, it becomes difficult to track where prospecting has already been done.

I suggest that instead of removing these points entirely, they should be displayed in black if none of the selected minerals are detected.

This would clearly indicate areas with no detected minerals while still allowing us to see where we've already prospected.

[Kaldo]

I had the same thought when using the filter, it would be very valuable to see even empty spots on the map when filtering by an ore so we know that there is nothing there. Seems like a simple enough change but it would help out a lot!