I see two issues in this aspect:
1: Correct a wrong scale on the current map used.
– As the data is only stored pr. measure point(I suspect!), simply being able to re-add the two messure points should ‘just’ provide new input to formulas used for visualization (that is done every time the user changes map anyway!)
2: Replace crappy floor plans with better ones!
Sometimes you simply have to snap pictures of fire escape plans in the hallway, in order to get the survey done. Being able to replace these with better pictures/CAD drawings would be awesome!
Here, the user needs to align/scale the new image to match the old one and then replace it.
If the replacing image is much better resolution, this could provide a better zoom factor as well…