OGC Technical Committee
Huntsville, 2006-03-08
GALEON – NERC/CCLRC experience
Andrew Woolf ([email protected])e-Science Centre, CCLRC Rutherford Appleton Lab
Acknowledgments:Dominic Lowe (British Atmospheric Data Centre)
Jon Blower (NERC Environmental Systems Science Centre)Nathan Bindoff, Glenn Hyland, Jason Roberts, Ian Cummings
(Tasmanian Partnership for Advanced Computing)NERC DataGrid team
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations
1. Consider CSML ‘Grid’ for irregular grid domains
<Grid srsName="urn:EPSG:geographicCRS:4979" srsDimension="3" dimension="2"> <gml:limits> <gml:GridEnvelope> <gml:low>0 7</gml:low> <gml:high>0 13</gml:high> </gml:GridEnvelope> </gml:limits> <gml:axisName>gridI</gml:axisName> <gml:axisName>gridJ</gml:axisName> <ordinate> <gridAxesSpanned>gridI gridJ</gridAxesSpanned> <sequenceRule order="+y+x">Linear</sequenceRule> <definesAxis xlink:href="#Lon"/> <axisValues> 1.00 1.10 1.20 1.30 1.40 1.45 1.50 1.55 1.60 1.50 1.45 1.35 1.30 1.20 1.10 1.18 1.27 1.36 1.46 1.48 1.57 1.65 1.71 1.62 1.58 1.50 1.48 1.40 ... </axisValues> </ordinate> ...</Grid>
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations
2. Support New Work Item Proposal for ISO 19111 (Spatial referencing by coordinates - extension for parametric values), OGC 06-013
(some informative examples motivated by CF conventions)
Scope: “To define an extension of ISO 19111:2005 covering coordinate referencing systems where the coordinates are physical or material properties measured by parameters, such as pressure, rather than linear distance measurements. It defines a conceptual schema for the description of spatio-parametric coordinate reference systems. These parametric spatial reference systems will be modelled so that they may be associated with an ISO 19111 [horizontal] spatial coordinate reference system to form a compound spatio-parametric coordinate reference system.”
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations
3. Rationalise binary encoding in GML (for coverage range and domain)
<gml:RectifiedGridCoverage gml:id="netcdf_ID0"> <gml:RectifiedGridDomain xlink:href="http://myserver/myfile.nc#temperature" xlink:role="http://netcdf/GMLOps/Grid/spatialDomain"/> <gml:rangeSet> <gml:File> <gml:rangeParameters> <gml:Quantity uom="degC"/> <fileReference>http://myserver/myfile.nc#temperature </fileReference> <fileStructure>Record Interleaved</fileStructure> <mimeType>application/x-netcdf</mimeType> </gml:rangeParameters> </gml:File> </gml:rangeSet></gml:RectifiedGridCoverage>
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations
4. Add “CF-netCDF” to allowed formats• HDF netCDF• HDF-EOS CF-netCDF
5. BBOX clarification w.r.t. CRS• e.g. EPSG:4979 (lat, lon, height)
• BBOX=lat1,lon1,height1,lat2,lon2,height2, not• BBOX=minx,miny,maxx,maxy,minz,maxz
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations
6. Harmonise WMS, WCS: BBOX and ELEVATION
• WCS 1.0.0:BBOX=minx,miny,maxx,maxy,minz,maxz
• WMS 1.3.0:BBOX=minx,miny,maxx,maxy&ELEVATION=minz/maxz/resz
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations7. Eliminate mandatory WIDTH (RESX), HEIGHT (RESY),
DEPTH (RESZ)• to enable arbitrary slicing through four dimensions• e.g., Hovmüller (timeseries) of winds from 110-190E
BBOX=110,-45,190,-45,1000,1000&TIME=2004-08-01/2004-08-31 HEIGHT (RESY) and DEPTH (RESZ) irrelevant
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations8. Clarify interpolation vs subsampling
• netCDF API:nc_get_vars_*(ncid,varid,start,count,stride,buf)
• OPeNDAP:http://opendapserver/dataset?var[start:stride:stop]
• WCS should support subsampling– behaviour of INTERPOLATION?
9. Conventions for exposing netCDF attributes in WCS metadata, e.g.:
• netCDF variable name WCS ‘CoverageOffering/name’ • CF ‘long_name’ WCS ‘CoverageOffering/label’• CF ‘standard_name’ WCS
‘CoverageOffering/rangeSet/RangeSet/label’
OGC Technical Committee
Huntsville, 2006-03-08
Recommendations
10.Clarify roles of ‘temporalDomain’ and ‘spatialDomain/EnvelopeWithTimePeriod’
• unclear whether ‘temporalDomain’ mandatory for time-dependant data
Experimental WCS (and full report) at: http://glue.badc.rl.ac.uk/cgi-bin/TPAC/WCS
