Projections
Jérôme Martin
gooogle at FREE.FR
Wed Jan 31 20:23:35 EST 2007
Hi Bradley,
it is normal if your raster is not correctly aligned with the 2 goods
shapefiles.
In fact, yours shapefiles are on the projection "GDA_1994_MGA_Zone_55",
so its implique mapserv knows where to place correctly the shapefiles data.
But for your raster, you don't have any information about the
projection. So it can't know in what projection and zone the data has to
be. (a bounding box exist in each zone, and are just translated from 6°
(maybe not in your reprojection, i don't know it, but UTM is the same
system of 2x60 zones to define the earth)).
So you can first try to put for each layer in your mapfile
PROJECTION
"init=epsg:xxxx" #where xxxx is the corresponding identifier of
the projection (check the share/proj/epsg file to do this) : in your
case, it is "init=epsg:28355".
END
to force mapserv to know from where the data comes. It is probably
useful only for the raster, but try to put again for shapefile in case
of it still doesn't work. (It always better to add this information in
each layer)
I hope i could help you,
sincerely,
Jérôme
Bradley Mclain a écrit :
> Hi
>
> I'm having some problems with projections in Mapserver. I have three
> pieces of data, 2 polygon shapefiles and a GeoTIFF raster image. I am
> trying to define their projections so that they align correctly as the
> raster is slightly off from the two shapefiles.
>
> I have managed to extract the geographical info from the files but I
> have no idea where I define it in the mapfile and what info I need to
> include (or what any of it means).
>
> I have attached the three text files which include the geographical
> data for each, can someone explain to me how to define these in a
> mapfile, eg where I need to do it and what info I need.
>
> Can you please include lots of detail and description so I can fully
> understand :)
>
> Thanks
>
> Brad
>
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>
> Layer name: DBW_Home_Bilbul_Cadastral_Boundary
> Geometry: Polygon
> Feature Count: 15
> Extent: (419320.137222, 6205167.425465) - (421949.715102, 6207719.690811)
> Layer SRS WKT:
> PROJCS["GDA_1994_MGA_Zone_55",
> GEOGCS["GCS_GDA_1994",
> DATUM["Geocentric_Datum_of_Australia_1994",
> SPHEROID["GRS_1980",6378137.0,298.257222101]],
> PRIMEM["Greenwich",0.0],
> UNIT["Degree",0.0174532925199433]],
> PROJECTION["Transverse_Mercator"],
> PARAMETER["False_Easting",500000.0],
> PARAMETER["False_Northing",10000000.0],
> PARAMETER["Central_Meridian",147.0],
> PARAMETER["Scale_Factor",0.9996],
> PARAMETER["Latitude_Of_Origin",0.0],
> UNIT["Meter",1.0]]
> LUID: Real (11.0)
> PLANTYPE: String (4.0)
> TAG: String (50.0)
> Area: Real (19.11)
> Perimeter: Real (19.11)
> Acres: Real (19.11)
> Hectares: Real (19.11)
> Bound_type: String (25.0)
> Prop_ID: String (30.0)
> OGRFeature(DBW_Home_Bilbul_Cadastral_Boundary):0
> LUID (Real) = 103663790
> PLANTYPE (String) = 13
> TAG (String) = 116//751728
> Area (Real) = 206766.29741414590
> Perimeter (Real) = 1930.52158953932
> Acres (Real) = 51.09308655258
> Hectares (Real) = 20.67662974141
> Bound_type (String) = Cadastre
> Prop_ID (String) = DBW_Home_Bilbul
> POLYGON ((419849.019570303731598
> 6205435.040179193019867,419680.452153401391115
> 6205707.173638857901096,420228.545299204241019
> 6206046.107636354863644,420397.849921675398946
> 6205772.639121992513537,419849.019570303731598 6205435.040179193019867))
>
> Layer name: DBW_Hemley_2593_Cadastral_Boundary
> Geometry: Polygon
> Feature Count: 3
> Extent: (422645.120770, 6208302.281805) - (423450.690420, 6208880.746240)
> Layer SRS WKT:
> PROJCS["GDA_1994_MGA_Zone_55",
> GEOGCS["GCS_GDA_1994",
> DATUM["Geocentric_Datum_of_Australia_1994",
> SPHEROID["GRS_1980",6378137.0,298.257222101]],
> PRIMEM["Greenwich",0.0],
> UNIT["Degree",0.0174532925199433]],
> PROJECTION["Transverse_Mercator"],
> PARAMETER["False_Easting",500000.0],
> PARAMETER["False_Northing",10000000.0],
> PARAMETER["Central_Meridian",147.0],
> PARAMETER["Scale_Factor",0.9996],
> PARAMETER["Latitude_Of_Origin",0.0],
> UNIT["Meter",1.0]]
> LUID: Real (11.0)
> PLANTYPE: String (4.0)
> TAG: String (50.0)
> Area: Real (19.11)
> Perimeter: Real (19.11)
> Acres: Real (19.11)
> Hectares: Real (19.11)
> Bound_type: String (40.0)
> Prop_ID: String (30.0)
> OGRFeature(DBW_Hemley_2593_Cadastral_Boundary):0
> LUID (Real) = 103664166
> PLANTYPE (String) = 13
> TAG (String) = 288//751728
> Area (Real) = 73981.56105988749
> Perimeter (Real) = 1173.94681513112
> Acres (Real) = 18.28124965142
> Hectares (Real) = 7.39815610599
> Bound_type (String) = Cadastre
> Prop_ID (String) = Hemley_2593
> POLYGON ((423067.736698167922441
> 6208782.058439230546355,423228.702213083277456
> 6208880.746239688247442,423450.690419794409536
> 6208521.27053206320852,423266.332749532884918
> 6208468.748745977878571,423260.736078957444988
> 6208477.574468746781349,423067.736698167922441 6208782.058439230546355))
>
> Driver: GTiff/GeoTIFF
> Size is 9530, 6552
> Coordinate System is `'
> Origin = (418485.188000000023749,6208828.519999999552965)
> Pixel Size = (0.609681177000000,-0.609608973000000)
> Metadata:
> AREA_OR_POINT=Area
> TIFFTAG_SOFTWARE=IMAGINE TIFF Support
> Copyright 1991 - 1999 by ERDAS, Inc. All Rights Reserved
> @(#)$RCSfile: etif.c $ $Revision: 1.9.1.2 $ $Date: 2001/12/05 00:33:12Z $
> TIFFTAG_XRESOLUTION=1
> TIFFTAG_YRESOLUTION=1
> TIFFTAG_RESOLUTIONUNIT=1 (unitless)
> Corner Coordinates:
> Upper Left ( 418485.188, 6208828.520)
> Lower Left ( 418485.188, 6204834.362)
> Upper Right ( 424295.450, 6208828.520)
> Lower Right ( 424295.450, 6204834.362)
> Center ( 421390.319, 6206831.441)
> Band 1 Block=9530x1 Type=Byte, ColorInterp=Red
> Band 2 Block=9530x1 Type=Byte, ColorInterp=Green
> Band 3 Block=9530x1 Type=Byte, ColorInterp=Blue
>
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