Mapnik-users,
I'm trying to display a raster geotiff image using mapnik2. Based on all the
documentation and example code, I've written an xml file to create a layer with
the appropriate style. In order to test this, I have a simple python script.
However, when I call "mapnik2.load_map(m, mapfile)" I get the message "Raster
Plugin: exception caught", which is a little vague. The resulting plot is
empty whether I'm using the "us" or "nozoom" levels in the python script
(different types of bbox coordinates). I've used this python script before for
plotting vector data with mapnik, so I believe the problem is with the xml
file. Any help on what I might be overlooking would be greatly appreciated.
Thanks,
Amy Maples
Noblis, Inc.
Python script:
#!/usr/bin/env python
# first arguement is xml file name
# second argument is zoom level(all lower case)--can be nozoom, us, state,
city, locale, street
import sys
import mapnik2
if not sys.argv[1:]:
sys.argv += ['climateTest.xml']
#sys.argv += ["argument1", "argument2", "argument3"]
if (len(sys.argv)<=2):
zoom='nozoom'
else:
zoom=sys.argv[2]
mapfile = sys.argv[1]
map_output = mapfile[:-4]+'_'+zoom+'.png'
m = mapnik2.Map(1000,500)
mapnik2.load_map(m, mapfile)
if (zoom=='nozoom'):
bbox = mapnik2.Box2d(mapnik2.Coord(-14911468.431, 2242177.475),
mapnik2.Coord(-6158842.809, 8775827.587))
elif (zoom=='us'):
bbox = mapnik2.Box2d(mapnik2.Coord(-133.952,219.444),
mapnik2.Coord(-55.577,61.647))
elif (zoom=='state'):
bbox = mapnik2.Box2d(mapnik2.Coord(-84,37), mapnik2.Coord(-76,40))
elif (zoom=='city'):
bbox = mapnik2.Box2d(mapnik2.Coord(-77,39), mapnik2.Coord(-77,39))
elif (zoom=='locale'):
bbox = mapnik2.Box2d(mapnik2.Coord(-77.242,38.8399),
mapnik2.Coord(-77.195,38.873))
elif (zoom=='street'):
bbox = mapnik2.Box2d(mapnik2.Coord(-77.219253,38.858257),
mapnik2.Coord(-77.211013,38.866544))
else:
bbox = mapnik2.Box2d(mapnik2.Coord(-180.0, -90.0), mapnik2.Coord(180.0,
90.0))
m.zoom_to_box(bbox)
mapnik2.render_to_file(m, map_output)
climateTest.xml file:
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE Map>
<Map 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 +wktext +no_defs">
<Style name="tk">
<Rule>
<RasterSymbolizer>
<RasterColorizer>
<ColorBand value="250"
color="rgb(238,130,238)" label="<0"></ColorBand>
<ColorBand value="260"
color="rgb(75,0,130)" midpoints="199"></ColorBand>
<ColorBand value="270"
color="rgb(0,0,255)" midpoints="199"></ColorBand>
<ColorBand value="280"
color="rgb(0,128,0)" midpoints="199"></ColorBand>
<ColorBand value="290"
color="rgb(255,205,0)" midpoints="199"></ColorBand>
<ColorBand value="300"
color="rgb(255,127,0)" midpoints="199"></ColorBand>
<ColorBand value="310"
color="rgb(196,2,51)"></ColorBand>
</RasterColorizer>
</RasterSymbolizer>
</Rule>
</Style>
<Layer name="RegCM_tk_NCAR_historical_1" 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 +wktext +no_defs">
<StyleName>tk</StyleName>
<Datasource>
<Parameter name="type">raster</Parameter>
<Parameter name="file">/home/amaples/new.tif</Parameter>
<Parameter name="lox">-14911468.431</Parameter>
<Parameter name="loy">2242177.475</Parameter>
<Parameter name="hix">-6158842.809</Parameter>
<Parameter name="hiy">8775827.587</Parameter>
</Datasource>
</Layer>
</Map>
GDALINFO new.tif:
Driver: GTiff/GeoTIFF
Files: new.tif
Size is 71, 53
Coordinate System is:
PROJCS["unnamed",
GEOGCS["unnamed ellipse",
DATUM["unknown",
SPHEROID["unnamed",6378137,0]],
PRIMEM["Greenwich",0],
UNIT["degree",0.0174532925199433]],
PROJECTION["Mercator_1SP"],
PARAMETER["central_meridian",0],
PARAMETER["scale_factor",1],
PARAMETER["false_easting",0],
PARAMETER["false_northing",0],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]]]
Origin = (-14911468.430740585550666,8775827.586873944848776)
Pixel Size = (123276.417201214062516,-123276.417201214062516)
Metadata:
AREA_OR_POINT=Area
Image Structure Metadata:
INTERLEAVE=BAND
Corner Coordinates:
Upper Left (-14911468.431, 8775827.587) (133d57'7.20"W, 61d38'47.76"N)
Lower Left (-14911468.431, 2242177.475) (133d57'7.20"W, 19d44'21.62"N)
Upper Right (-6158842.809, 8775827.587) ( 55d19'32.97"W, 61d38'47.76"N)
Lower Right (-6158842.809, 2242177.475) ( 55d19'32.97"W, 19d44'21.62"N)
Center (-10535155.620, 5509002.531) ( 94d38'20.09"W, 44d16'50.94"N)
Band 1 Block=71x14 Type=Float64, ColorInterp=Gray
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