After some work, I managed to extract some PNGs out of a GIS we have at work. This GIS has some polygons in which addresses are surrounded by them. I managed to create an extractor in Python and to align the overlays and google maps pretty well, although it is not perfect. My question is, what I'm doing wrong or overlooking when making these transformations, to make them align perfectly.
For example, I have this image:
As you can see, it aligns, but not perfectly, I found out a method for alignment using the markers, and dragging them to modify the overlay, but when there are 64 images, it is a very long process.
The overlay PNG comes from a different coordinate system (WGS72 BE UTM). What I did was a Python script that downloads all the tiles necessary for 2 given points (SouthWest,NorthEast), and then prints out the boundaries for all the tiles so I can place them onto Google Maps.
This is an example of the program run:
X1: 348724 Y1: 6294333 X2: 354334 Y2: 6300043 Delta: 4100 Processing... 4 images will be downloaded... image: 0001 limits: 348724 , 6294333 ; 352824 , 6298433 1 image: 0002 limits: 348724 , 6298433 ; 352824 , 6302533 2 image: 0003 limits: 352824 , 6294333 ; 356924 , 6298433 3 image: 0004 limits: 352824 , 6298433 ; 356924 , 6302533 4
The data is in Santiago, Chile.
Then I convert those limits to Google Maps coordinates (WGS84) and place them. However, the results are not precise. It would be great to hear your ideas. I hope explained myself correctly.