[postgis-devel] GDAL WKT Raster Driver weekly report #3

[Pierre Racine]

Hi Jorge,

You should actually say: "This integration between raster and vectors in ***PostGIS*** is related with other methods like..." There is no such things as ST_Intersection, ST_Union in GDAL... It is true however that this integration work will rely on the GDAL library.

Pierre

From: postgis-devel-bounces at postgis.refractions.net [mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of Jorge Arévalo
Sent: 17 juin 2009 16:27
To: PostGIS Development Discussion
Subject: Re: [postgis-devel] GDAL WKT Raster Driver weekly report #3

Hi Pierre,

I've read the introduction again, and totally agree: shows confusion, concept mixing. But I must say that I wrote these sentences very late at night, and in different moments, when I had finished the rest of the document. Now, I think that they have no sense... 

I understand the limits between :
- the work in GDAL (A driver able to read a new type of raster: a new PostGIS type called "WKT Raster")
- the work in PostGIS (this new type that adds raster support in PostGIS)

This new PostGIS type will be able to be integrated in raster/vector operations with vector data: ST_Intersection, ST_Union, etc. This integration between raster and vectors in GDAL is related with other methods like, as you said, GDALPolygonize, GDALContourGenerate and GDALRasterizeLayers), not directly with my job, of course. 

I apologize for that. I feel really stupid just now, I see the error perfectly. I'm going to correct the document just now. And, by the way, I'm going to add an "Acknowledgements" section.

Many thanks for your help, and sorry again for this stupid mistake

Best Regards
Jorge

On Wed, Jun 17, 2009 at 3:41 PM, Pierre Racine <Pierre.Racine at sbf.ulaval.ca> wrote:
Hi Jorge,

At first sight there seems to be a confusion between "raster/vector integration in PostGIS" VS "raster/vector integration in GDAL".

When you say "And these new type of GDAL data will be used to perform seamless operations with VECTOR DATA (Geometry type, in OGR-Syntax), from OGR library." and "This new abstract Raster objects will be used together with the OGR Geometry objects in functions like ST_Intersection or ST_Union. " you are mixing what we intend to do in PostGIS and something that does not really exist in GDAL/OGR (except for the GDALPolygonize, GDALContourGenerate and GDALRasterizeLayers methods). Your goal, it seems to me, should not be to care about raster/vector operations in GDAL but just to be able to read WKT Rasters from PostGIS so that GDAL can do whatever is can do with raster. Implementing raster/vector seemless operations over GDAL/OGR is a very interesting and desirable project, but I don't think it is part of this driver project. You should not have to care about OGR at all.

Pierre


From: postgis-devel-bounces at postgis.refractions.net [mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of Jorge Arévalo
Sent: 16 juin 2009 00:11
To: soc at lists.osgeo.org; gdal-dev at lists.osgeo.org; PostGIS Development Discussion
Subject: [postgis-devel] GDAL WKT Raster Driver weekly report #3

Here is the report #3

http://www.gis4free.org/blog/2009/06/16/gsoc-09-weekly-report-3-0506-1206/

And, as usual, the project can be followed here

http://trac.osgeo.org/gdal/wiki/WKTRasterDriver

Best regards
Jorge
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