[11727] | 1 | #!/usr/bin/env python |
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| 2 | #------------------------------------------------------- |
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| 3 | # Translates between lat/long and the slippy-map tile |
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| 4 | # numbering scheme |
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| 5 | # |
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| 6 | # http://wiki.openstreetmap.org/index.php/Slippy_map_tilenames |
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| 7 | # |
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| 8 | # Written by Oliver White, 2007 |
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| 9 | # This file is public-domain |
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| 10 | #------------------------------------------------------- |
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| 11 | from math import * |
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| 12 | |
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| 13 | def numTiles(z): |
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| 14 | return(pow(2,z)) |
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| 15 | |
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| 16 | def sec(x): |
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| 17 | return(1/cos(x)) |
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| 18 | |
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| 19 | def latlon2relativeXY(lat,lon): |
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| 20 | x = (lon + 180) / 360 |
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| 21 | y = (1 - log(tan(radians(lat)) + sec(radians(lat))) / pi) / 2 |
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| 22 | return(x,y) |
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| 23 | |
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| 24 | def latlon2xy(lat,lon,z): |
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| 25 | n = numTiles(z) |
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| 26 | x,y = latlon2relativeXY(lat,lon) |
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| 27 | return(n*x, n*y) |
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| 28 | |
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| 29 | def tileXY(lat, lon, z): |
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| 30 | x,y = latlon2xy(lat,lon,z) |
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| 31 | return(int(x),int(y)) |
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| 32 | |
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| 33 | def xy2latlon(x,y,z): |
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| 34 | n = numTiles(z) |
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| 35 | relY = y / n |
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| 36 | lat = mercatorToLat(pi * (1 - 2 * relY)) |
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| 37 | lon = -180.0 + 360.0 * x / n |
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| 38 | return(lat,lon) |
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| 39 | |
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| 40 | def latEdges(y,z): |
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| 41 | n = numTiles(z) |
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| 42 | unit = 1 / n |
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| 43 | relY1 = y * unit |
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| 44 | relY2 = relY1 + unit |
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| 45 | lat1 = mercatorToLat(pi * (1 - 2 * relY1)) |
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| 46 | lat2 = mercatorToLat(pi * (1 - 2 * relY2)) |
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| 47 | return(lat1,lat2) |
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| 48 | |
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| 49 | def lonEdges(x,z): |
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| 50 | n = numTiles(z) |
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| 51 | unit = 360 / n |
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| 52 | lon1 = -180 + x * unit |
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| 53 | lon2 = lon1 + unit |
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| 54 | return(lon1,lon2) |
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| 55 | |
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| 56 | def tileEdges(x,y,z): |
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| 57 | lat1,lat2 = latEdges(y,z) |
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| 58 | lon1,lon2 = lonEdges(x,z) |
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| 59 | return((lat2, lon1, lat1, lon2)) # S,W,N,E |
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| 60 | |
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| 61 | def mercatorToLat(mercatorY): |
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| 62 | return(degrees(atan(sinh(mercatorY)))) |
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| 63 | |
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| 64 | def tileSizePixels(): |
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| 65 | return(256) |
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| 66 | |
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| 67 | def tileLayerExt(layer): |
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| 68 | if(layer in ('oam')): |
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| 69 | return('jpg') |
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| 70 | return('png') |
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| 71 | |
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| 72 | def tileLayerBase(layer): |
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| 73 | layers = { \ |
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| 74 | "tah": "http://dev.openstreetmap.org/~ojw/Tiles/tile.php/", |
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| 75 | "oam": "http://oam1.hypercube.telascience.org/tiles/1.0.0/openaerialmap-900913/", |
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| 76 | "mapnik": "http://tile.openstreetmap.org/mapnik/" |
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| 77 | } |
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| 78 | return(layers[layer]) |
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| 79 | |
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| 80 | def tileURL(x,y,z,layer): |
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| 81 | return "%s%d/%d/%d.%s" % (tileLayerBase(layer),z,x,y,tileLayerExt(layer)) |
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| 82 | |
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| 83 | if __name__ == "__main__": |
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| 84 | for z in range(0,17): |
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| 85 | x,y = tileXY(51.50610, -0.119888, z) |
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| 86 | |
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| 87 | s,w,n,e = tileEdges(x,y,z) |
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| 88 | print "%d: %d,%d --> %1.3f :: %1.3f, %1.3f :: %1.3f" % (z,x,y,s,n,w,e) |
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| 89 | #print "<img src='%s'><br>" % tileURL(x,y,z) |
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