[mapserver-users] Mapserver WCS - how to return native pixel resolution data?

[Alexander Petkov]

On Thu, Mar 19, 2009 at 12:48 PM, Roger André <randre at gmail.com> wrote:
> Sorry for the spam, I think I found the answer.  Both RESX and RESY
> need to be positive values.  Using that, I am able to get back data
> that matches the original data.
>
> Thanks,
>
> Roger
> --
>
> On Thu, Mar 19, 2009 at 11:36 AM, Roger André <randre at gmail.com> wrote:
>> Hi Alexander,
>>
>> Thanks for the response.  Yes, I am using a GetCoverage request that
>> looks like this:
>>
>> http://localhost/cgi-bin/mapserv?map=/var/www/mapfiles/netCDF/netcdf.map
>> &SERVICE=wcs
>> &VERSION=1.0.0
>> &REQUEST=GetCoverage
>> &COVERAGE=elev
>> &CRS=EPSG:4326
>> &BBOX=125,50,130,55
>> &WIDTH=600
>> &HEIGHT=600
>> &FORMAT=image/grid
>>
>> The source is a single-band image, and the data is correctly returned
>> as either a single-band GeoTIFF, or an ASCII Grid, depending on which
>> FORMAT I specify in the WCS string.
>>
>> What I would like to do is eliminate the WIDTH and HEIGHT parameters
>> from the request, and just return whatever is available in the BBOX
>> area.  When I remove them from the request, I get an error that says I
>> either need HEIGHT and WIDTH, or RESX and RESY.  When I restructure
>> the command to include RESX and RESY (see below), I get an "Out of
>> memory" error.
>>
>> http://localhost/cgi-bin/mapserv?map=/var/www/mapfiles/netCDF/netcdf.map
>> &SERVICE=wcs
>> &VERSION=1.0.0
>> &REQUEST=GetCoverage
>> &COVERAGE=elev
>> &CRS=EPSG:4326
>> &BBOX=125,50,130,55
>> &FORMAT=image/grid
>> &RESX=.033&RESY=-.033
>>
>> I believe I should be able to use the pixel dimensions that are
>> reported back to me in a DescribeCoverage request, which show them to
>> be:
>>
>> <gml:offsetVector>0.033333333333333 0</gml:offsetVector>
>> <gml:offsetVector>0 -0.033333333333333</gml:offsetVector>
>>
>> Thanks for the help,
>>
>> Roger

Hi Roger:

Glad to know that you got the problem solved. Do you mind sharing your
OUTPUTFORMAT configurations in your mapfile if you have them
configured, particularly for the ASCII grid format.

Also, are you using a mapserver release older than any of the 5.4
betas? I am using 5.2.1 and I see the result of the GetCoverage
request being offset by a half pixel (the pixel size of my data). Bug
reports indicate that this offset will be fixed for the 5.4 release.


Thanks in advance,
Alex