source: subversion/applications/rendering/png2tileinfo/README @ 10854

Last change on this file since 10854 was 10568, checked in by deelkar, 12 years ago

amend README for png2tileinfo

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1README for png2tileinfo
2-----------------------
3
4This is the "source" for the oceantiles_12.dat file used in
5close-areas.pl and in lowzoom.pl of the tilesAtHome project, as
6well as the tahngo t@h server.
7
8The oceantiles_12.dat file contains two bits for every level-12
9tile in the world, specifying whether it is a land tile, a sea tile,
10a coastal tile, or unknown.
11
12The file is easy to access by the programs using it, but difficult
13to edit. So here is the "source data" in the form of a large PNG
14file 4096x4096 pixels for the whole planet, in which each pixel
15corresponds to one level-12 tile and may have one of four colours:
16
17white - coastline intersects with this tile
18green - no coastline intersect, land tile
19blue -  no coastline intersect, sea tile
20black - unknown
21
22If you find errors in the data file - i.e. an inland area rendered
23blue or a sea area not rendered blue -, you can simply fix the PNG file
24with any image editor, then run png2tileinfo, and you have a new
25data file. (Please make sure to upload both the .png file that you
26changed and the .dat file created!)
27
28Please note that the code is picky about the colours used. Nothing
29but "pure" colors will do - blue has to be 0,0,255, green has to be
300,255,0, black is 0,0,0 and white 255,255,255.
31
32Usage:
33% cd applications/rendering/png2tileinfo
34% svn update
35% perl png2tileinfo.pl check 3762 2471
36oceantiles_12.png(3762, 2471) = 3 (mixed)
37% perl png2tileinfo.pl set 3762 2471 land
38% perl png2tileinfo.pl
39
40[wait until file generated...]
41
42% svn commit
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