mirror of
https://github.com/openstreetmap/mapnik-stylesheets.git
synced 2025-07-21 10:43:38 +00:00
d2bddd8654
git-svn-id: http://svn.openstreetmap.org/applications/rendering/mapnik@26276 b9d5c4c9-76e1-0310-9c85-f3177eceb1e4
86 lines
2.8 KiB
Python
Executable File
86 lines
2.8 KiB
Python
Executable File
#!/usr/bin/env python
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try:
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import mapnik2 as mapnik
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except:
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import mapnik
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import sys, os
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# Set up projections
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# spherical mercator (most common target map projection of osm data imported with osm2pgsql)
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merc = mapnik.Projection('+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs +over')
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# long/lat in degrees, aka ESPG:4326 and "WGS 84"
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longlat = mapnik.Projection('+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs')
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# can also be constructed as:
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#longlat = mapnik.Projection('+init=epsg:4326')
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# ensure minimum mapnik version
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if not hasattr(mapnik,'mapnik_version') and not mapnik.mapnik_version() >= 600:
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raise SystemExit('This script requires Mapnik >=0.6.0)')
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if __name__ == "__main__":
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try:
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mapfile = os.environ['MAPNIK_MAP_FILE']
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except KeyError:
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mapfile = "osm.xml"
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map_uri = "image.png"
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#---------------------------------------------------
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# Change this to the bounding box you want
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#
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bounds = (-6.5, 49.5, 2.1, 59)
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#---------------------------------------------------
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z = 10
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imgx = 500 * z
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imgy = 1000 * z
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m = mapnik.Map(imgx,imgy)
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mapnik.load_map(m,mapfile)
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# ensure the target map projection is mercator
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m.srs = merc.params()
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if hasattr(mapnik,'Box2d'):
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bbox = mapnik.Box2d(*bounds)
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else:
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bbox = mapnik.Envelope(*bounds)
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# Our bounds above are in long/lat, but our map
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# is in spherical mercator, so we need to transform
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# the bounding box to mercator to properly position
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# the Map when we call `zoom_to_box()`
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transform = mapnik.ProjTransform(longlat,merc)
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merc_bbox = transform.forward(bbox)
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# Mapnik internally will fix the aspect ratio of the bounding box
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# to match the aspect ratio of the target image width and height
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# This behavior is controlled by setting the `m.aspect_fix_mode`
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# and defaults to GROW_BBOX, but you can also change it to alter
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# the target image size by setting aspect_fix_mode to GROW_CANVAS
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#m.aspect_fix_mode = mapnik.GROW_CANVAS
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# Note: aspect_fix_mode is only available in Mapnik >= 0.6.0
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m.zoom_to_box(merc_bbox)
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# render the map to an image
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im = mapnik.Image(imgx,imgy)
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mapnik.render(m, im)
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im.save(map_uri,'png')
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sys.stdout.write('output image to %s!\n' % map_uri)
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# Note: instead of creating an image, rendering to it, and then
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# saving, we can also do this in one step like:
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# mapnik.render_to_file(m, map_uri,'png')
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# And in Mapnik >= 0.7.0 you can also use `render_to_file()` to output
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# to Cairo supported formats if you have Mapnik built with Cairo support
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# For example, to render to pdf or svg do:
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# mapnik.render_to_file(m, "image.pdf")
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#mapnik.render_to_file(m, "image.svg")
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