FWIW,<br><br>I have not found managing image attributes in relational tables that refer to rasters stored in a flat file system to be problematic. It was not difficult to create a toolset that manages updating the tables as the images change.
<br><br>It feels like an impedance mismatch to try and force large raster objects into a relational table system.<br><br>The combination of postgis, GDAL and mapserver is particularly potent. As GDAL abstracts raster access and allows homogeneous access to GeoTIFFs as well as JPEG2000 images (and others), I find I can store images as I choose and then migrate as necessary. I've also found performance excellent.
<br><br>GDAL manages the Kakadu issue by simply providing an adapter and leaving the acquisition of the source up to the installer; why would this not work equally well for postGIS ?<br><br>John Novak<br><br><div><span class="gmail_quote">
On 10/24/06, <b class="gmail_sendername">Marshall, Steve</b> <<a href="mailto:smarshall@wsi.com">smarshall@wsi.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div>
<div><font face="Arial" size="2"><span>Over the past
several months, I've seen a number of postings regarding support in PostGIS for
raster data. The email threads tend to look like this:</span></font></div>
<div><font face="Arial" size="2"><span>---</span></font></div>
<div><font face="Arial" size="2"><span>Poster:
</span></font></div>
<div><font face="Arial" size="2"><span>I'd like to have
support for raster data in PostGIS.</span></font></div>
<div><font face="Arial" size="2"><span></span></font> </div>
<div><font face="Arial" size="2"><span>Responder: </span></font></div>
<div><font face="Arial" size="2"><span>If you are just
going to put the whole image in the database, then take the complete image back
out, what's the point. Why do you think storing in the RDB would be better
than managing raster data in files?</span></font></div>
<div><font face="Arial" size="2"><span></span></font> </div>
<div><font face="Arial" size="2"><span>Poster:
</span></font></div>
<div><font face="Arial" size="2"><span>I would not have to
manage the interactions between the RDB and a file-based database, the images
would follow transactional semantics, and the raster data would be network
accessible. Additionally, I could use PostGIS spatial queries to
relate vector data to raster data, and maybe even write some
additional raster manipulation functions, all of which would be built into the
database.</span></font></div>
<div><font face="Arial" size="2"><span></span></font> </div>
<div><font face="Arial" size="2"><span>Responder:</span></font></div>
<div><font face="Arial" size="2"><span>That stuff sounds
neat, but the performance issues are unworkable. Performance with large
images will be terrible if we use anything other than flat
files.</span></font></div>
<div><font face="Arial" size="2"><span>---</span></font></div>
<div><font face="Arial" size="2"><span>Generally, the
debate ends here. This time I'd like to see if the conversation could go
in another direction.</span></font></div>
<div><font face="Arial" size="2"><span></span></font><snip></div></div></blockquote></div><br>