Hello, I am trying to put a dense raster (representing digital television coverage) onto a Google Map. The raster is originally in UTM coordinates (UTM zone 32N), in ArcMap. To tile the raster, I convert it to the Google Web Mercator projection (also called EPSG:900913), export it as a .png file and then create the tiles using John D. Coryat's perl tiling script. That script takes as input the png raster and the lat-long of the southwest and northeast corners of the png. (The extent of the raster in ArcMap is of course in Google Web Mercator coords, so I use cs2cs under Linux to convert to lat-long, i.e WGS84 or EPSG:4326 for the script sw and ne corners).
The link to a test page with the tiled raster is http://213.88.244.237/danmarks_radio/test/countyimagetiles.htm (my experiments are on-going so the link may not work) Now (finally), the question: The tiled raster is not positioned correctly, there is an error of a few hundred meters. This is especially visible in the east of the map, on the west coast of the island Bornholm. There, you can see a band of yellow and red pixels that should be just inside the coastline, but they are just outside instead (the band represents a region with poorer digital TV coverage). How can I get a more accurate positioning? Also worth noticing is that the same positioning error occurs when I put the coverage raster onto a Google map using a single ground overlay. Any help or advice would be appreciated. I can also provide more info if necessary, e.g. cs2cs commandline, perl tiling script commandline etc. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Maps API" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/Google-Maps-API?hl=en -~----------~----~----~----~------~----~------~--~---
