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

[Roger André]

You're right, 1/2 pixel offset is definitely present. What a pain.
Any idea when the 5.4 stable release is expected?  I see that a beta
release is available currently.
--

On Thu, Mar 19, 2009 at 1:55 PM, Roger André <randre at gmail.com> wrote:
> Sure thing.  Here are the OUTPUTFORMAT declarations I have:
>
> OUTPUTFORMAT
>  NAME "GEOTIFF_FLOAT"
>  DRIVER 'GDAL/GTiff'
>  MIMETYPE 'image/tiff'
>  IMAGEMODE FLOAT32
>  EXTENSION 'tif'
> END
>
> OUTPUTFORMAT
>  NAME "ASCII_GRID"
>  DRIVER 'GDAL/AAIGrid'
>  MIMETYPE 'image/grid'
>  IMAGEMODE FLOAT32
>  EXTENSION 'asc'
> END
>
> I'll have to check my output data more closely to see if the 1/2 pixel
> offset exists.  I've only looked at it in a cursory way so far.  The
> version of MapServer I'm using is 5.2.0
> --
>
> On Thu, Mar 19, 2009 at 12:14 PM, Alexander Petkov <greenkov at gmail.com> wrote:
>> 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
>>
>