The regular grid constraint is in fact a part of the WCS specification
(at least for 1.x, which has been implemented for TDS). Under the scope
section of the spec, you'll find:
"Grid coverages have a domain comprised of regularly spaced locations
along 0, 1, 2, or 3 axes of a spatial coordinate reference system.
Their domain may also have a time dimension, which may be regularly or
The WCS interface, while limited in this version to regular grid
coverages, is designed to extend in future versions to other coverage
types defined in OGC Abstract Specification Topic 6, "The Coverage Type"
Having said that, WCS 2.0 (freshly released a couple of weeks ago) does
allow for irregular grids, which is really exciting :)
Hope that helps.
On 11/11/10 6:46 PM, Derrick.Wong@xxxxxxxx wrote:
I have been using THREDDS for awhile now, and have been serving
“regularly” gridded data via the WCS server. There are some datasets
which I thought were gridded but I can only GetCapabilities document
I have read the specification for THREDDS Web Coverage Service
and it says:
1. Data files must contain gridded data.
2. The NetCDF-Java Common Data Model must be able to identify the
coordinates system used. Check this by opening in the Grid Panel
of the ToolsUI
application. There should be one or more variables shown as a GeoGrid.
3. Currently due to WCS and GeoTIFF limitations, the X,Y and (if it
exists) Z axes must be regularly spaced.
What exactly constitutes the Thredds definition of “regular” and
“irregular” data? Apart from using ToolsUI to check, what are the actual
specifications of regularly gridded data which can be served by THREDS WCS?
Thank you for your time.
Software Engineer *|* Spatial Information Services Stack (SISS) Project
Phone: +61 8 6436 8945
derrick.wong@xxxxxxxx <mailto:derrick.wong@xxxxxxxx> *|* www.csiro.au
Address: Spatial Information Services Stack (SISS), 26 Dick Perry
Avenue, Kensington WA 6151, Australia
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