[postgis-users] adding raster caps to postgis
Bart van den Eijnden
BEN at Syncera-ITSolutions.NL
Tue Sep 13 00:30:28 PDT 2005
I think there is a demand for sure, seeing also the Oracle Georaster.
Are you aware of this initiative, it was posted on the gdal-dev list recently:
I've been playing a bit with GDAL driver implementation and as I am
quite interested in database development, I 've decided to write a
Postgis wrapper for GDAL. I've used the Postgis CHIP datatype to store
rasters in PostgreSQL.
Basically, the driver can read files with a pixel definition of 8 or
16 bits. It can deal with 1 or 4 bands (GREY_SCALE, PALETTE and RGBA).
I've only tested to import PNG, BMP, JPEG and TIF files and I think
the driver is not stable yet with any other formats. The driver is
supposed to be capable of dealing with projections if Postgis was
built with the proj4 library.
I do think it could be good to move some of the functions from the
GDAL Driver source code to Postgis source. However, this would require
I contact Postgis development team and I prefer to finalize the driver
before, as it is really easier to test and develop.
I have contacted Frank so that this new experimental driver can soon
be part of the global GDAL source tree.
If you can't wait unil then or if you're interested in testing, you
can download the source code from this address:
http://simon.benjamin.free.fr/pgchip/ and follow the installation
Any suggestions, comments, questions or help are welcome.
Bart van den Eijnden
Syncera IT Solutions
2600 AG DELFT
email: BEN at Syncera-ITSolutions.nl
>>> "Jeff D. Hamann" <jeff.hamann at forestinformatics.com> 13-9-2005 5:53 >>>
I've been thinking about adding (or trying to add) raster storage
capabilites to postgis and before I spend time floundering in the code, I
wanted to post a few questions to the mailing list before I worked myself
into exhaustion. So,
1) Is there a demand for adding raster capabilites (for people other than
myself)? For my work, I would use it in a intersecting from polygons kind
of way for image classification within GRASS or write out a shape file.
2) What is a real assessment of what would be involved (for people that
have already thought about this but didn't post a message to the mailing
list)? WOuld gdal be a good approach or would the code have to be from the
ground up? Would using GDAL add to the complexity of code dependencies to
the point where it would be prohibitive or do do most people that use
postgis already have gdal (compiled into GRASS?)
3) Assuming this would have to pass the ISO 19124/19130 standard test (if
there is one at GCR), is there anyone that could assist me to ensure I
understand all that that implies since I've never coded anything to be
compliant with ISO standards?
4) Is there an open source project that already has this capability?
Jeff D. Hamann
Forest Informatics, Inc.
PO Box 1421
Corvallis, Oregon 97339-1421
jeff.hamann at forestinformatics.com
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