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This document outlines critical recommendations for improving e-Science data management based on the experience of Andrew Woolf and contributions from various experts. Key suggestions include consideration for irregular grid domains using CSML, support for ISO 19111 spatial referencing extensions, rationalization of binary encoding in GML, clarification of BBOX parameters in WMS and WCS standards, and improvements in handling temporal and spatial domains. These recommendations aim to advance interoperability and data accessibility in environmental sciences.
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GALEON – NERC/CCLRC experience Andrew Woolf (A.Woolf@rl.ac.uk) 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
Recommendations • 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>
Recommendations • 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.”
Recommendations • 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>
Recommendations • Add “CF-netCDF” to allowed formats • HDF netCDF • HDF-EOS CF-netCDF • 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 ü
Recommendations • 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
Recommendations • Eliminate mandatory WIDTH (RESX), HEIGHT (RESY), DEPTH (RESZ) • to enable arbitrary slicing through four dimensions • e.g., Hovmüller (timeseries) of winds from 110-190EBBOX=110,-45,190,-45,1000,1000&TIME=2004-08-01/2004-08-31 HEIGHT (RESY) and DEPTH (RESZ) irrelevant
Recommendations • 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? • 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’
Recommendations • 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