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LuisFelizTirado

Improving TileProxy -- need some technical help

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Guest cbuchner1

Such a shame - it's already on the hard drive, but no one can get past the proprietary format.

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Guest oldnemesis

>Ouch! That's twice the amount of downloads just to recognize>land/water.Correct. But it is not supposed to work in realtime either. I could wait for a night.> Also the URL format is somewhat different between map and satellite views.Correct, but neither is a problem anyway.>And it would only work where Google actually has maps.Which includes a lot already, and the coverage is increasing (just added Thailand, Russia etc. recently).>I bet that's not available for many far out regions of the world.The satellite images of acceptable quality are not always available either. Also you can use other map sources if available.

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Guest cbuchner1

Cooking up this topic once again: How to create smooth land/water transitions with Tileproxy.I see the NASA database covers coast lines at 30m resolution (1 arc second) accuracy. That is not particularly exact. NASA provides ESRI shape files in squares of 1 degree lat/long in zipped form. These files are typically 40kb-500kb in size.Shipping this database with Tileproxy would be a bit too much, so why not have Tileproxy download this on demand from NASA's FTP site? ;-)The files do have very predictable names, derived from their coordinate. There are C libraries to download + unzip these files and to load+parse the ESRI shape files. That won't be a problem.This data would have to be rendered to a bitmap to be usable for my purpose. There are several graphics libraries, cairo and antigrain graphics (agg), just to name a few that are capable of doing anti-aliasing.What I need to generate is a water blend masks for DXT3 textures. These texture formats support a 4 bit alpha channel. Maybe I should also dither the blend mask to smooth out the transitions caused by the 4 bit alpha encoding.Tileproxy would only create DXT3 textures for tiles that are at coast lines, the rest remains DXT1 encoded. I could also make use of the DXT1 single bit alpha channel to output water-only tiles (saves about 1/2 of the space compared to DXT3 textures).This seems like an awful lot of work to do. Plus the alpha channel rendering might be a bit slow. But it would only affect a very limited number of tiles.But hey, people want to use their float planes. And with Tileproxy they can't...Christian

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Those are very clever solutions to a complicated problem, Christian. Please let us know how it turns out, as it seems to be very interesting.Best regards.Luis

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