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andrewharvey/mapnik_render_static_map.py

Created October 16, 2011 10:31
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Revisions

  1. andrewharvey revised this gist Aug 6, 2012. 1 changed file with 2 additions and 3 deletions.
    5 changes: 2 additions & 3 deletions mapnik_render_static_map.py
    View file
    Original file line number Diff line number Diff line change
    @@ -11,9 11,8 @@
    # rights to this work.
    # http://creativecommons.org/publicdomain/zero/1.0/

    # Following process was used for testing
    # http://173.230.151.169/tiles/fosm/mapnik/17/120590/78656.png
    # should match ./render_map_preview.py -x 151.21170043945312 -y -33.871555787081476 -z 17 -w 256 -h 256
    # For testing the tile 17/120590/78656 should match the output of
    # ./render_map_preview.py -x 151.21170043945312 -y -33.871555787081476 -z 17 -w 256 -h 256

    # that tile has centre (-33.871555787081476, 151.21170043945312) -> 16832809.4949049 -4011568.11846262
    # and bounds (-33.87041555094183, 151.2103271484375),(-33.87269600798948, 151.21307373046875)
  2. andrewharvey revised this gist Dec 10, 2011. 1 changed file with 0 additions and 0 deletions.
    Empty file modified mapnik_render_static_map.py
    100644 → 100755
    View file
    Empty file.
  3. @invalid-email-address Anonymous revised this gist Oct 16, 2011. 1 changed file with 3 additions and 3 deletions.
    6 changes: 3 additions & 3 deletions mapnik_render_static_map.py
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    Original file line number Diff line number Diff line change
    @@ -1,6 1,6 @@
    #!/usr/bin/env python

    # This script is like generate_image.py from the OSM mapnik code,
    # This script is like generate_image.py from the OSM Mapnik code,
    # but it renders based on a given centre point, zoom and final image pixel size

    # Author: Andrew Harvey <[email protected]>
    @@ -38,7 38,7 @@
    # WGS lat/long source projection of centre
    longlat = mapnik.Projection(' proj=longlat ellps=WGS84 datum=WGS84 no_defs')

    # ensure minimum mapnik version
    # ensure minimum Mapnik version
    if not hasattr(mapnik,'mapnik_version') and not mapnik.mapnik_version() >= 600:
    raise SystemExit('This script requires Mapnik >=0.6.0)')

    @@ -86,7 86,7 @@
    minx = merc_centre.x - dx
    maxx = merc_centre.x dx

    # grow the height bbox, as we only accuratly set the width bbox
    # grow the height bbox, as we only accurately set the width bbox
    m.aspect_fix_mode = mapnik.aspect_fix_mode.ADJUST_BBOX_HEIGHT

    bounds = mapnik.Box2d(minx, merc_centre.y-10, maxx, merc_centre.y 10) # the y bounds will be fixed by mapnik due to ADJUST_BBOX_HEIGHT
  4. @invalid-email-address Anonymous created this gist Oct 16, 2011.
    98 changes: 98 additions & 0 deletions mapnik_render_static_map.py
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    Original file line number Diff line number Diff line change
    @@ -0,0 1,98 @@
    #!/usr/bin/env python

    # This script is like generate_image.py from the OSM mapnik code,
    # but it renders based on a given centre point, zoom and final image pixel size

    # Author: Andrew Harvey <[email protected]>
    # License: CC0 http://creativecommons.org/publicdomain/zero/1.0/
    #
    # To the extent possible under law, the person who associated CC0
    # with this work has waived all copyright and related or neighboring
    # rights to this work.
    # http://creativecommons.org/publicdomain/zero/1.0/

    # Following process was used for testing
    # http://173.230.151.169/tiles/fosm/mapnik/17/120590/78656.png
    # should match ./render_map_preview.py -x 151.21170043945312 -y -33.871555787081476 -z 17 -w 256 -h 256

    # that tile has centre (-33.871555787081476, 151.21170043945312) -> 16832809.4949049 -4011568.11846262
    # and bounds (-33.87041555094183, 151.2103271484375),(-33.87269600798948, 151.21307373046875)
    # which are projected as (gdaltransform -s_srs ' proj=longlat ellps=WGS84 datum=WGS84 no_defs' -t_srs ' 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')
    # xmin=16832656.6208484
    # ymin=-4011415.24440605
    # xmax=16832962.3689615
    # ymax=-4011720.99251919

    # dx=306 ie. so 306 in projected units for this one tile

    try:
    import mapnik2 as mapnik
    except:
    import mapnik

    import getopt, sys, os

    # target projection
    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')

    # WGS lat/long source projection of centre
    longlat = mapnik.Projection(' proj=longlat ellps=WGS84 datum=WGS84 no_defs')

    # ensure minimum mapnik version
    if not hasattr(mapnik,'mapnik_version') and not mapnik.mapnik_version() >= 600:
    raise SystemExit('This script requires Mapnik >=0.6.0)')

    if __name__ == "__main__":
    # get arguments
    try:
    opts, args = getopt.getopt(sys.argv[1:], "m:x:y:z:w:h:o:", ["mapfile=", "centrex=", "centrey=", "zoom=", "width=", "height=", "output="])
    except getopt.GetoptError, err:
    print str(err)
    #usage()
    sys.exit(2)

    for o, a in opts:
    if o in ("-m", "--mapfile"):
    mapfile = a
    elif o in ("-x", "--centrex"):
    centrex = float(a)
    elif o in ("-y", "--centrey"):
    centrey = float(a)
    elif o in ("-z", "--zoom"):
    zoom = int(a)
    elif o in ("-w", "--width"):
    width = int(a)
    elif o in ("-h", "--height"):
    height = int(a)
    elif o in ("-o", "--output"):
    output = a

    # make a new Map object for the given mapfile
    m = mapnik.Map(width, height)
    mapnik.load_map(m, mapfile)

    # ensure the target map projection is mercator
    m.srs = merc.params()

    # transform the centre point into the target coord sys
    centre = mapnik.Coord(centrex, centrey)
    transform = mapnik.ProjTransform(longlat, merc)
    merc_centre = transform.forward(centre)

    # 360/(2**zoom) degrees = 256 px
    # so in merc 1px = (20037508.34*2) / (256 * 2**zoom)
    # hence to find the bounds of our rectangle in projected coordinates and - half the image width worth of projected coord units
    dx = ((20037508.34*2*(width/2)))/(256*(2 ** (zoom)))
    minx = merc_centre.x - dx
    maxx = merc_centre.x dx

    # grow the height bbox, as we only accuratly set the width bbox
    m.aspect_fix_mode = mapnik.aspect_fix_mode.ADJUST_BBOX_HEIGHT

    bounds = mapnik.Box2d(minx, merc_centre.y-10, maxx, merc_centre.y 10) # the y bounds will be fixed by mapnik due to ADJUST_BBOX_HEIGHT
    m.zoom_to_box(bounds)

    # render the map image to a file
    mapnik.render_to_file(m, output)

    sys.stdout.write('output image to %s!\n' % output)