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atkinstache
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README.md

Atkinstache

Atkinstache is a TileStache provider for generating stylized black and white halftone, or "dithered", map tiles using another tileset as its input. The halftone effect is accomplished using Bill Atkinson's original dithering algorithm created for the first Apple Macintosh computers.

Typically you would use satellite imagery but there's nothing to stop you from using a different source.

How to

It exposes a single provider named atkinstache.dithering.Provider and you invoke it in your TileStache config like this:

"layers": {
	"microsoft_aerial": {
		"provider": { "name": "proxy", "provider": "MICROSOFT_AERIAL" }
	},

	"dithering": {
		"provider": {
			"class": "atkinstache.dithering.Provider",
			"kwargs": {
				"source_layer": "microsoft_aerial",
				"skip_on_checksum": "1",
				"checksum": "afeeb6c8b0a5edb1b9ef94d1d652f41b"
			}
		}
	}
}

If the skip_on_checksum flag is true then the contents of each new tile (from the source_layer provider) will be MD5 hashed and compared to the checksum value. If the two match the tile will not be dithered. You might want to do this for tile sets that send a unique tile for those areas that lack coverage.

Other stuff

By default Atkinstache will use a pure Python implementation of the dithering algorithm to filter images. If the C-based atk Python implimentation is installed the package will use that instead.

See also: