Greetings,
When you convert a map to World Partition it asks if you wish to generate minimap, however how would go about doing this from a map that was already in World Partion format when you started designing i?
Or how would you update the minimap in World Partition View if you have made changes? -I am guessing this would be the answer for the above question.
You just need to run commandlet to regenerate minimap.
Something like this:
"..\UnrealEditor.exe" "..\XXX.uproject" -run=WorldPartitionBuilderCommandlet WorldPartition.umap -Builder=WorldPartitionMiniMapBuilder -AllowCommandletRendering -log=MiniMap.txt
You can also just do this from the Build menu: Build->Build Minimap
As shown here in the documentation:
https://docs.unrealengine.com/5.0/en-US/world-partition-in-unreal-engine/