Hi Stefan,
in OGC the Web Coverage Service (WCS) is "in charge" of raster data [1].
Coverages are special feature types upon which WCS offers specific
functionality, like subsetting. The WCS standard has no resemblance with
WKT Raster that is known to me.
A coverage actually is more than only rasters, according to ISO 19123
and OGC Abstract Topic 6 (which are identical), it can also represent
point clouds, irregular grids, meshes, and more.
And it is not only 2-D, but can have any spatio-temporal dimension, such
as 1D time series, 2D imagery, 3D image time series (x/y/t) or geology
data (x/y/z), 4D climate and ocean data (x/y/z/t).
The latest adopted version of WCS is 2.0 (August 2010). It will be
uploaded in a week or so, currently you see WCS 1.1.2.
An interactive demo of WCS-based services you find at EarthLook [2].
There you also find practical examples of OGC's raster query language
standard, Web Coverage Processing Service (WCPS), including a sandbox to
throw in your own queries. All services on said site, from 1D to 4D, are
based on the open-source rasdaman raster database server [3] running on
top of PostgreSQL.
Hope that helps,
Peter (WCS group co-chair and standards editor)
[1] www.ogcnetwork.net/wcs
[2] www.earthlook.org
[3] www.rasdaman.org
On 10/13/2010 10:02 AM, Stefan Keller wrote:
Hi PostGIS users list,
I'm playing around with the PostGIS Raster type with the goal to get
the principles and to be able to put this exciting new development in
relation e.g. to standards and other implementations.
I'm aware of WKT and WKB in vector knowing OGC Simple Feature Spec.
I'm now wondering about the usage of the notion Well Known Text (WKT)
and Well Known Binary (WKB) for raster.
What I understand from the PostGIS Raster project home page
(http://trac.osgeo.org/postgis/wiki/WKTRaster) that JPEG and TIFF
formats are supported.
=> Do you mean by WKB that these formats are specified in public
accessible specs.?
=> How about the spec. of WKT raster?
-S.
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Dr. Peter Baumann
- Professor of Computer Science, Jacobs University Bremen
www.faculty.jacobs-university.de/pbaumann
mail: p.baum...@jacobs-university.de
tel: +49-421-200-3178, fax: +49-421-200-493178
- Executive Director, rasdaman GmbH Bremen (HRB 147737)
www.rasdaman.com, mail: baum...@rasdaman.com
tel: 0800-rasdaman, fax: 0800-rasdafax, mobile: +49-173-5837882
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