Salut Pierre, Hallo Peter Many thanks for your explanations.
Pierre answered: > >=> Do you mean by WKB that these formats are specified in public > >accessible specs.? > > > As I said: no. They are not specified in public. I wish there would have been > a public spec to tell me how to store raster but there is not. I'd like to understand and support this better: 1. You write "They are not specified in public.": But now they are at least in the sense of "PostGIS WKB", aren't they? Now there is the PostGIS documentation (http://trac.osgeo.org/postgis/wiki/WKTRaster/Documentation01) as well as the source code publicly available. 2. Wen you say "I wish there would have been a public spec to tell me how": Do you mean that there code/encoding gives still much room fore enhancements? This would be an opportunity to be discussed but it also would mean that "PostGIS WKB" would'nt be stable. Yours. S. 2010/10/13 Pierre Racine <pierre.rac...@sbf.ulaval.ca>: > Hi Stefan, > >>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. > > There is no WKT, WKB standards for raster and there is no standard (that I > know of) to store raster in a database. WKT raster borrowed the WKT, WKB > concepts to provide a way to directly create and read raster stored in the > database. > > You will find the specification for our WKB format in this document: > http://trac.osgeo.org/postgis/browser/trunk/raster/doc/RFC2-WellKnownBinaryFormat > > No specifications for WKT have been defined yet even if it was planned > originally and it gave WKT raster its names. Note that we renamed the type > "PostGIS Raster". > > WCS defines ways to query coverage data in general (raster, vector, point > cloud, etc...) but in no way tells you what should be a raster and how to > store it. It should not be too complicated to implement WCS as SQL functions > over WKT 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. > > PostGIS Raster does not "supports" other raster formats. It is a format (or > better a "type") in itself. We have a Python "converter" (or a "loader" in DB > terminology) that convert (or load) raster from any raster format supported > by GDAL (in read mode) to PostGIS Raster. In this sence, it "supports" all > those raster formats. > >>=> Do you mean by WKB that these formats are specified in public >>accessible specs.? > > As I said: no. They are not specified in public. I wish there would have been > a public spec to tell me how to store raster but there is not. > >>=> How about the spec. of WKT raster? > > You will find the best description of PostGIS Raster in those pages: > > http://trac.osgeo.org/postgis/wiki/WKTRaster/Documentation01 > > Hope this help. > > Pierre > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users > _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
