[mapserver-users] PDF and SVG only shows last georeferenced raster layer
Anzel, Phil - Fort Collins, CO
Phil.Anzel at ftc.usda.gov
Fri Jun 11 15:45:52 PDT 2010
Hi,
I think there is a defect when using multiple raster data layers with PDF or SVG image formats: only the last geo-referenced raster layer is drawn. This problem does not exist if the output is PNG.
To demonstrate this problem, retrieve two adjacent JPEG tile files from Microsoft's Virtual Earth, using URLs:
(west tile) http://ecn.t0.tiles.virtualearth.net/tiles/r021323222.jpg?g=409&mkt=en-US&shading=hill&n=z
(east tile) http://ecn.t0.tiles.virtualearth.net/tiles/r021323223.jpg?g=409&mkt=en-US&shading=hill&n=z
The tiles should be saved as files r021323222.jpg and r021323223.jpg, respectively.
Create world files to accompany these. For the west tile, create r021323223.wld:
305.748113140705
0.0000000000
0.0000000000
-305.748113140705
-11897270.5785311
5087648.60266133
For the east, create r021323223.wld:
305.748113140705
0.0000000000
0.0000000000
-305.748113140705
-11818999.0615671
5087648.60266133
Here is the map file, with the addition of a red outline around the west tile and a green outline around the east one:
MAP
IMAGETYPE png
SIZE 512 256
CONFIG 'PROJ_LIB' 'C:\ms4w\proj\nad\'
PROJECTION 'init=epsg:3857' END # Web Mercator
EXTENT -11900270.578531099 5006377.08569731 -11737727.5446031 5090648.6026613303
UNITS meters
LAYER
NAME 'left_tile'
# retrieve from http://ecn.t0.tiles.virtualearth.net/tiles/r021323222.jpg?g=409&mkt=en-US&shading=hill&n=z
data 'r021323222.jpg'
type raster
status on
END
LAYER
NAME 'right_tile'
# retrieve from http://ecn.t0.tiles.virtualearth.net/tiles/r021323223.jpg?g=409&mkt=en-US&shading=hill&n=z
data 'r021323223.jpg'
type raster
status on
END
LAYER
NAME 'left_outline'
STATUS on
TYPE line
FEATURE #...right edge shifted left 153 meters (about half a tile pixel)
WKT 'LINESTRING(
-11818999.0615671 5009377.08569731,
-11897423.578531099 5009377.08569731,
-11897423.578531099 5087648.60266133,
-11818999.0615671 5087648.60266133,
-11818999.0615671 5009377.08569731)'
END
CLASS
STYLE
COLOR 255 0 0
END
END
END
LAYER
NAME 'right_outline'
STATUS on
TYPE line
FEATURE #...left edge shifted right 153 meters (about half a tile pixel)
WKT 'LINESTRING(
-11818846.0615671 5009377.08569731,
-11740727.5446031 5009377.08569731,
-11740727.5446031 5087648.60266133,
-11818846.0615671 5087648.60266133,
-11818846.0615671 5009377.08569731)'
END
CLASS
STYLE
COLOR 0 255 0
END
END
END
END
Note that for PNG output, both tiles are shown. If you change the image type to SVG or PDF, only the last raster layer, the east tile, is shown.
Is this a defect? Short of externally aggregating the source bitmaps into a single bitmap outside of MapServer, is there a possible workaround? Is this associated with failure of OPACITY to work with SVG and PDF?
I'm using MapServer version 5.6.3 (MS4W distribution) under Windows XP Pro 2002 SP3. The problem was demonstrated with use of the "drawmap.exe" command-line utility.
Thanks in advance.
- Phil Anzel
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