I have the Andes raster mapping for the UK in OSGB36 format. In addition, I
have vector GPS information in lat/long decimal degree WGS84 format.
Additionally, I have some extra data sets also in WGS84 format (mainly
NAVTEQ). The mapserver is interfacing to another system through mapscript
that requires to recieve and send lat/long co-ordinates in decimal degrees.
My problem is this: when I display the composite map, I get a vertical
"squishing" of the raster layer as (presumably) gdal is translating the
image on the fly into WGS84 space. OSGB36 is a pretty flat (and square!)
projection, but I end up with a nicely curved and vertically foreshortened
one with text that is then very difficult to read.
What I would ideally like is for mapserver to not attempt to manipulate the
raster at all, but allow it to be projected effectively in OSGB dimensions
but with lat / long units of measure instead of the OSGB units. This would
ideally mean that my WGS84 data would reproject into effectively a "flat"
space but still with lat /long units. Hope that makes sense, is it possible?
Or is it something daft I'm doing with the PROJECTION that's causing all
this fuss, I hope so! Can anybody offer me some guidance?
Here's my map def:
OUTPUTFORMAT
NAME png
DRIVER "GD/PNG"
IMAGEMODE pc256
END
MAP
STATUS ON
SIZE 500 380
EXTENT -11.0 44.0 9.0 59.0
UNITS dd
SHAPEPATH "/var/gis/live"
IMAGECOLOR 247 245 222
FONTSET "/var/gis/live/fonts/fonts.txt"
PROJECTION
"proj=latlong"
"ellps=WGS84"
"datum=WGS84"
"nodefs"
END
LAYER
NAME andesl7
PROJECTION
"proj=tmerc"
"lat_0=49.000000000"
"lon_0=-2.000000000"
"k=0.9996012717"
"x_0=400000.000"
"y_0=-100000.000"
"ellps=airy"
"datum=OSGB36"
"no_defs"
END
STATUS DEFAULT
TILEINDEX "al7.shp"
TILEITEM "location"
TYPE RASTER
END
LAYER
CONNECTIONTYPE postgis
NAME custpoi_poly
PROJECTION
"proj=latlong"
"ellps=WGS84"
"datum=WGS84"
END
DATA "the_geom from custpoi_poly"
CONNECTION "user=user password=password dbname=dbname
host=127.0.0.1"
STATUS DEFAULT
TYPE POLYGON
LABELITEM "description"
CLASSITEM "symbol"
TRANSPARENCY 30
CLASS
STYLE
COLOR 255 0 0
END
LABEL
ANTIALIAS TRUE
SIZE medium
COLOR 255 0 0
TYPE bitmap
FORCE TRUE
BACKGROUNDCOLOR 255 255 255
BACKGROUNDSHADOWCOLOR 255 0 0
POSITION AUTO
END
END
END
#
END # Map File
Many thanks in advance,
Dave Pearson
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