Exporting Google/Bing map tiles does not anti-alias at all?

Aaron

I'm exporting Google or Bing maps tiles from very high quality GeoTIFF data using File>Export>Export Web Format... The projections don't match but it appears to be being re-projected correctly as part of the export process.

The exported tiles I get are not anti-aliased - see below; the "nice" parts are standard Google Maps data and the dotty parts are my generated tiles over the top. I've produced tiles between zoom levels 4 and 19 and it happens at all levels.

I've found a couple of anti-aliasing/interpolation options in the configuration menu and turned them on but neither made a difference.

I also found this post from 2009 which seemed to have the opposite problem at some zoom levels - hope this wasn't "broken" to fix his issue? (as these results aren't really usable for any purpose)  

All my tests so far have been using jpg tiles and png's for the edges needing transparency.