Source Code for Module viewer.lib.tilenames

 1  #!/usr/bin/env python 
 2  """Translates between lat/long and the slippy-map tile numbering scheme 
 3   
 4  http://wiki.openstreetmap.org/index.php/Slippy_map_tilenames 
 5   
 6  @author: Oliver White 
 7  @date: 2007 
 8  @license: This file is public-domain. 
 9   
10  """ 
11   
12  __author__ = "Oliver White" 
13  __copyright__ = "(c) 2007, Oliver White" 
14  __license__ = "This file is public-domain." 
15   
16  from math import * 
17   
18 -def numTiles(z): 
19      return(pow(2, z)) 
20   
21 -def sec(x): 
22      return(1 / cos(x)) 
23   
24 -def latlon2relativeXY(lat, lon): 
25      x = (lon + 180) / 360 
26      y = (1 - log(tan(radians(lat)) + sec(radians(lat))) / pi) / 2 
27      return(x, y) 
28   
29 -def latlon2xy(lat, lon, z): 
30      n = numTiles(z) 
31      x, y = latlon2relativeXY(lat, lon) 
32      return(int(n * x), int(n * y)) 
33     
34 -def tileXY(lat, lon, z): 
35      x, y = latlon2xy(lat, lon, z) 
36      return(int(x), int(y)) 
37   
38 -def xy2latlon(x, y, z): 
39      n = numTiles(z) 
40      relY = y / n 
41      lat = mercatorToLat(pi * (1 - 2 * relY)) 
42      lon = -180.0 + 360.0 * x / n 
43      return(lat, lon) 
44     
45 -def latEdges(y, z): 
46      n = numTiles(z) 
47      unit = 1 / n 
48      relY1 = y * unit 
49      relY2 = relY1 + unit 
50      lat1 = mercatorToLat(pi * (1 - 2 * relY1)) 
51      lat2 = mercatorToLat(pi * (1 - 2 * relY2)) 
52      return(lat1, lat2) 
53   
54 -def lonEdges(x, z): 
55      n = numTiles(z) 
56      unit = 360 / n 
57      lon1 = -180 + x * unit 
58      lon2 = lon1 + unit 
59      return(lon1, lon2) 
60     
61 -def tileEdges(x, y, z): 
62      lat1, lat2 = latEdges(y, z) 
63      lon1, lon2 = lonEdges(x, z) 
64      return((lat2, lon1, lat1, lon2)) # S,W,N,E 
65   
66 -def mercatorToLat(mercatorY): 
67      return(degrees(atan(sinh(mercatorY)))) 
68   
69 -def tileSizePixels(): 
70      return(256) 
71   
72 -def tileLayerExt(layer): 
73      if(layer in ('oam')): 
74          return('jpg') 
75      return('png') 
76   
77 -def tileLayerBase(layer): 
78      layers = {"tah": "http://cassini.toolserver.org:8080/http://a.tile.openstreetmap.org/+http://toolserver.org/~cmarqu/hill/", 
79                #"tah": "http://tah.openstreetmap.org/Tiles/tile/", 
80                "oam": "http://oam1.hypercube.telascience.org/tiles/1.0.0/openaerialmap-900913/", 
81                "mapnik": "http://tile.openstreetmap.org/mapnik/" 
82      } 
83      return(layers[layer]) 
84     
85 -def tileURL(x, y, z, layer): 
86      return "%s%d/%d/%d.%s" % (tileLayerBase(layer), z, x, y, tileLayerExt(layer)) 
87   
88  if __name__ == "__main__": 
89    for z in range(0,18): 
90      x,y = tileXY(52.37930, 9.72310, z) 
91       
92      s,w,n,e = tileEdges(x,y,z) 
93      print "%d: %d,%d --> %1.3f :: %1.3f, %1.3f :: %1.3f" % (z,x,y,s,n,w,e) 
94      #print "<img src='%s'><br>" % tileURL(x,y,z) 
95