Change History (7)
comment:1 by , 15 years ago
Owner: | changed from | to
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comment:2 by , 14 years ago
Status: | new → assigned |
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comment:3 by , 14 years ago
Cc: | added |
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comment:4 by , 14 years ago
I tried investigating this service a bit, and issued:
http://motherlode.ucar.edu:8080/thredds/wcs/fmrc/NCEP/GFS/Alaska_191km/runs/NCEP-GFS-Alaska_191km_RUN_2009-07-28T12:00:00Z?SERVICE=WCS&REQUEST=GetCapabilities&VERSION=1.0.0
but in response I got:
<?xml version="1.0" encoding="UTF-8"?> <ServiceExceptionReport xmlns="http://www.opengis.net/ogc" version="1.2.0"> <ServiceException>Failed to open dataset, [/fmrc/NCEP/GFS/Alaska_191km/runs/NCEP-GFS-Alaska_191km_RUN_2009-07-28T12:00:00Z].</ServiceException> </ServiceExceptionReport>
I'm not sure if the old file is just no longer available, or if I am doing something wrong but there isn't much I can do about this ticket currently.
comment:5 by , 14 years ago
Frank, The following is the XML control file used:
<WCS_GDAL><ServiceURL>http://motherlode.ucar.edu:8080/thredds/wcs/fmrc/NCEP/GFS/Alaska_191km/runs/NCEP-GFS-Alaska_191km_RUN_2009-12-10T06:00:00Z?</ServiceURL><CoverageName>Absolute_vorticity</CoverageName><Version>1.0.0</Version><Timeout>90</Timeout><Resample>nearest%20neighbor</Resample></WCS_GDAL>
I looked at the return of DescribeCoverage, listed below. I think the problem is the special SRS, "EPSG:-3[Stereographic]".
- <spatialDomain> - <EnvelopeWithTimePeriod srsName="urn:ogc:def:crs:OGC:1.3:CRS84"> <gml:pos dimension="2">114.61043998234297 18.285366597346187</gml:pos> <gml:pos dimension="2">360.0 90.0</gml:pos> <gml:timePosition>2009-12-10T06:00:00Z</gml:timePosition> <gml:timePosition>2009-12-15T06:00:00Z</gml:timePosition> </EnvelopeWithTimePeriod> - <gml:RectifiedGrid srsName="EPSG:-3[Stereographic]" dimension="3"> - <gml:limits> - <gml:GridEnvelope> <gml:low>0 0 0</gml:low> <gml:high>44 38 3</gml:high> </gml:GridEnvelope> </gml:limits> <gml:axisName>x</gml:axisName> <gml:axisName>y</gml:axisName> <gml:axisName>z</gml:axisName> - <gml:origin> <gml:pos>-4952.874701817127 -6857.989752814494 850.0</gml:pos> </gml:origin> <gml:offsetVector>190.5 0.0 0.0</gml:offsetVector> <gml:offsetVector>0.0 190.5 0.0</gml:offsetVector> <gml:offsetVector>0.0 0.0 -200.0</gml:offsetVector> </gml:RectifiedGrid> </spatialDomain> - <temporalDomain> <gml:timePosition>2009-12-10T06:00:00Z</gml:timePosition> <gml:timePosition>2009-12-10T12:00:00Z</gml:timePosition> <gml:timePosition>2009-12-10T18:00:00Z</gml:timePosition> <gml:timePosition>2009-12-11T00:00:00Z</gml:timePosition> <gml:timePosition>2009-12-11T06:00:00Z</gml:timePosition> <gml:timePosition>2009-12-11T12:00:00Z</gml:timePosition> <gml:timePosition>2009-12-11T18:00:00Z</gml:timePosition> <gml:timePosition>2009-12-12T00:00:00Z</gml:timePosition> <gml:timePosition>2009-12-12T06:00:00Z</gml:timePosition> <gml:timePosition>2009-12-12T12:00:00Z</gml:timePosition> <gml:timePosition>2009-12-12T18:00:00Z</gml:timePosition> <gml:timePosition>2009-12-13T00:00:00Z</gml:timePosition> <gml:timePosition>2009-12-13T06:00:00Z</gml:timePosition> <gml:timePosition>2009-12-13T12:00:00Z</gml:timePosition> <gml:timePosition>2009-12-13T18:00:00Z</gml:timePosition> <gml:timePosition>2009-12-14T00:00:00Z</gml:timePosition> <gml:timePosition>2009-12-14T06:00:00Z</gml:timePosition> <gml:timePosition>2009-12-14T12:00:00Z</gml:timePosition> <gml:timePosition>2009-12-14T18:00:00Z</gml:timePosition> <gml:timePosition>2009-12-15T00:00:00Z</gml:timePosition> <gml:timePosition>2009-12-15T06:00:00Z</gml:timePosition> </temporalDomain> </domainSet> - <rangeSet> - <RangeSet> <description xmlns="">Absolute_vorticity 1/s true Absolute_vorticity @ isobaric</description> <name>Absolute_vorticity</name> <label>Absolute_vorticity @ isobaric</label> - <axisDescription> - <AxisDescription> <name>Vertical</name> <label>isobaric2</label> - <values> <singleValue>850.0</singleValue> <singleValue>700.0</singleValue> <singleValue>500.0</singleValue> <singleValue>250.0</singleValue> </values> </AxisDescription> </axisDescription> - <nullValues> <singleValue>NaN</singleValue> </nullValues> </RangeSet> </rangeSet> - <supportedCRSs> <requestCRSs>OGC:CRS84</requestCRSs> <responseCRSs>EPSG:-3[Stereographic]</responseCRSs> </supportedCRSs> - <supportedFormats> <formats>GeoTIFF</formats> <formats>GeoTIFF_Float</formats> <formats>NetCDF3</formats> </supportedFormats> - <supportedInterpolations> <interpolationMethod>none</interpolationMethod> </supportedInterpolations> </CoverageOffering> </CoverageDescription>
comment:6 by , 14 years ago
Resolution: | → wontfix |
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Status: | assigned → closed |
I discovered that OGC:CRS84 was not being interpreted, and I have fixed this in trunk (r18544). However, it is not clear this was important. I was still getting this error:
<ServiceException code="InvalidParameterValue" locator="BBOX">BBOX [-5048.12470181713,-6572.23975281449,-4667.12470181713,-6953.23975281449] minimum point larger than maximum point.</ServiceException>
Looking at the offset/vector from the RectifiedGrid description I noticed things were 3D:
<origin> <pos>-4952.874701817127 -6857.989752814494 850.0</pos> </origin> <offsetVector>190.5 0.0 0.0</offsetVector> <offsetVector>0.0 190.5 0.0</offsetVector> <offsetVector>0.0 0.0 -200.0</offsetVector>
so I tried a 3D BBOX but got an error indicating only 2D is allowed. The 2nd offset vector is normally negative in Y, but not for this server. This results in the first Y value in the BBOX being greater than the second as the BBOX is explicitly supposed to be lower left, upper right (not minx,miny,maxx,maxy), a point made clear in the specification OGC 05-076 9.2.2.7. Nevertheless, I tried switching the Y values and got somewhat further:
<ServiceException code="InvalidParameterValue" locator="CRS">Request CRS [EPSG:4326] not allowed [OGC:CRS84].</ServiceException>
I'm not sure why the request is being made in EPSG:4326 instead of the SRS of the rectified grid (EPSG:-3[Stereographic]) so I tried using that as the SRS, but I got a similar error. It appears the only coordinate system allowed is OGC:CRS84 even though that is not the SRS in which the grid is described. I tried that with a BBOX in lat/long and adding a TIME parameter in the area and it worked to some extent. It produced a GeoTIFF file, but the georeferencing of that file was pretty screwy:
http://motherlode.ucar.edu:8080/thredds/wcs/fmrc/NCEP/GFS/Alaska_191km/runs/NCEP-GFS-Alaska_191km_RUN_2009-12-10T06:00:00Z?SERVICE=WCS&VERSION=1.0.0&REQUEST=GetCoverage&COVERAGE=Absolute_vorticity&FORMAT=GeoTIFF&BBOX=120,19,122,21&WIDTH=2&HEIGHT=2&CRS=OGC:CRS84 Geotiff_Information: Version: 1 Key_Revision: 1.0 Tagged_Information: ModelTiepointTag (2,3): 0 0 0 -4952874.7018171310.2471855061594 0 ModelPixelScaleTag (1,3): 0 190500 0 End_Of_Tags. Keyed_Information: GTModelTypeGeoKey (Short,1): ModelTypeProjected GTRasterTypeGeoKey (Short,1): RasterPixelIsArea GeographicTypeGeoKey (Short,1): GCS_WGS_84 ProjectedCSTypeGeoKey (Short,1): User-Defined PCSCitationGeoKey (Ascii,7): "Snyder" ProjectionGeoKey (Short,1): User-Defined ProjLinearUnitsGeoKey (Short,1): Linear_Meter ProjCoordTransGeoKey (Short,1): CT_Stereographic ProjCenterLongGeoKey (Double,1): 0 ProjNatOriginLatGeoKey (Double,1): 90 ProjScaleAtNatOriginGeoKey (Double,1): 1 ProjFalseEastingGeoKey (Double,1): 0 ProjFalseNorthingGeoKey (Double,1): 0 End_Of_Keys. End_Of_Geotiff.
In particular the 0 for ModelPixelScaleTag makes the file degenerate. Also, oddly the file was returned in a sort of Polar Stereographic, instead of the CRS84 geographic coordinate system requested. At this point I'm reasonably convinced that the service is non-standard in so many ways that it would be damaging to the WCS driver to try and make it work with this service.
I don't think there is much else to do, unless there is a contact at ucar who would like to defend the compliance of this service.
Gao,
What XML control file do you use for this service?