[mapserver-users] HDF Data projection in MapServer

[Jeff McKenna]

Venkat,

Here are my quick thoughts:

- what is the projection of the original geotiff file?  I often have to 
go to the source of the data (where I found the data) and look for 
metadata stating the original projection
- once I know the original projection, then you can either manually 
specify the PROJ.4 parameters in your projection object (invaluable page 
for this PROJ.4 parameter definitions: 
http://trac.osgeo.org/proj/wiki/GenParms), or find an EPSG code that 
matches your source projection.  How to define a projection object in 
the mapfile is described at: 
http://www.mapserver.org/mapfile/projection.html

Yes this is tricky.

-jeff

-- 
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/


Reddem wrote:
> Hi Everybody,
> 
> I am trying to display HDF files using MapServer, and upto some extent
> i have done it. Still i am facing problem with the projection of map.
> 
> and MapFile Layer looks like this:
> 
>           LAYER
>                NAME wise_io
>                #DATA 'o.tif'
>                DATA
> 'HDF5:"C:/ms4w/apps/HDFData/data/output.h5"://Mapped_-_Composited_mapped'
>                DUMP TRUE
>                TYPE RASTER
>                STATUS ON
>                CLASSITEM "[pixel]"
>                CLASS
>                        EXPRESSION ([pixel] > 0)
>                        STYLE
>                                COLOR 0 0 255
>                        END
>                END
>                PROJECTION
>                                      {{{{       ................    }}}}
>                END
>        END
> 
> and GDAL INFO for used HDF data is :
> 
> .......................
> Driver: HDF5Image/HDF5 Dataset
> Files: none associated
> Size is 3630, 2530
> Coordinate System is:
> GEOGCS["WGS 84",
>    DATUM["WGS_1984",
>        SPHEROID["WGS 84",6378137,298.257223563,
>            AUTHORITY["EPSG","7030"]],
>        TOWGS84[0,0,0,0,0,0,0],
>        AUTHORITY["EPSG","6326"]],
>    PRIMEM["Greenwich",0,
>        AUTHORITY["EPSG","8901"]],
>    UNIT["degree",0.0174532925199433,
>        AUTHORITY["EPSG","9108"]],
>    AUTHORITY["EPSG","4326"]]
> Corner Coordinates:
> Upper Left  (    0.0,    0.0)
> Lower Left  (    0.0, 2530.0)
> Upper Right ( 3630.0,    0.0)
> Lower Right ( 3630.0, 2530.0)
> Center      ( 1815.0, 1265.0)
> Band 1 Block=3630x1 Type=Float32, ColorInterp=Undefined
>  Metadata:
>    Mapped - Composited mapped:Projection Category=IDL
>    Mapped - Composited mapped:Projection Name=Cylindrical
>    Mapped - Composited mapped:Source=A2010021053000_CHL.L2_LAC
>    Mapped - Composited mapped:units=mg m^-3
>    Mapped - Composited mapped:Slope=1.000000
>    Mapped - Composited mapped:Intercept=0.000000
>    Mapped - Composited mapped:Scaling=linear
>    Mapped - Composited mapped:Limit=4 62 27 95
>    Mapped - Composited mapped:Projection ID=8
>    Mapped - Composited mapped:Latitude Center=0
>    Mapped - Composited mapped:Longitude Center=78.5
>    Mapped - Composited mapped:Isotropic=1
>    Mapped - Composited mapped:Rotation=0
>    Mapped - Composited mapped:Position=0 0 1 1
>    Mapped - Composited mapped:Scale=0
>    Mapped - Composited mapped:Central_Azimuth=0
>    Mapped - Composited mapped:HDF4_OBJECT_TYPE=SDS
>    Mapped - Composited mapped:HDF4_OBJECT_NAME=Mapped - Composited mapped
>    Mapped - Composited mapped:HDF4_REF_NUM=2d
> ..............................................................................
> 
> I have created the GeoTiff using gdal_translate and projected it and
> it works well.
>>> gdal_translate -ot Byte -of GTiff -b 1 -a_ullr 62 4 95 27
>>> HDF5:"output.h5"://Mapped_-_Composited_mapped o.tif.
> 
> I am facing problem with projection of HDF data set which is 1 KM
> gridded dataset. and as without defining Projection Derivative it is
> showing somewhere else in the map.  can anyone help me in this regard
> to define Projection section of HDF data layer.
>