Frank,<br><br>Sorry for the mistake, the Well Known Text format I write
on the CRS definition file comes from the OSRExportToWkt function, in
OGR, not in PROJ.4. I agree that WKT is the best option, as it is not
software specific.
<br><br>
I will read about tile caching proposals, as you suggest, it sounds interesting.<br>
<br>Best regards,<br><br>Jordi<br><br><br><br><div><span class="gmail_quote">2006/11/15, Frank Warmerdam <<a href="mailto:warmerdam@pobox.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">warmerdam@pobox.com
</a>>:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Jordi wrote:<br>> Frank,<br>><br>> I agree that the GeoQuadTree GDAL driver should be under the MIT/X<br>> license used in the rest of the project.<br><br>Jordi,<br><br>Ah, cool. Then inclusion should be no problem. Lets make sure it
<br>makes it in before 1.4.0 release.<br><br>> At first I included the CRS definition in the same XML metadata file,<br>> but later I thought it would be more useful as a separate file, with<br>> .prj extension. This CRS file IS the definition in Well Known Text
<br>> format, as is returned from PROJ.4 library. Do you think it would be<br>> better to include it in the same XML metadata file ?<br><br>Ah. I just read the FAQ entry on the format, which I don't think<br>mentions the CRS file. A seperate .prj file with the wkt coordinate system
<br>should be fine.<br><br>You say "in Well Known Text format, as returned from PROJ.4 library".<br>The well known text format is not used or produced by the PROJ.4 library<br>so either you are really using PROJ.4
definitions (not WKT) or you really<br>mean as returned by OGRSpatialReference.<br><br>WKT usually starts with PROJCS or GEOGCS while PROJ.4 strings include<br>something like +proj=.<br><br>I think we should be using WKT as it is not so software specific.
<br><br>> I've started working on including the choice for JPEG, JPEG2000 or TIFF<br>> as alternatives to PNG for the format of the tiles. I would like also to<br>> support multi-bands with TIFF or with multiple PNGs/JPGs.
<br><br>cool<br><br>> You are absolutely right that sacrificing a RGB color for nondata is not<br>> a good idea in JPEG.<br>><br>> I don't know if I understand what you mean about a "standard tile<br>> cache". I'm sorry that I didn't study enough the GDAL core, and I didn't
<br>> know about the block cache. I'll try to use it: I implemented my own<br>> tile cache, but only as a consequence of my ignorance in GDAL internals.<br><br>This isn't a GDAL thing at all. Various web obsessed folks from projects
<br>like OpenLayers, ka-map, and others have been trying to hash out a standard<br>approach to web accessable tile caches such as those used by Google maps,<br>and WorldWind. So that web tile caches could be shared more effectively
<br>by different software packages. I think the following urls capture some<br>of that planning/discussion/thinking though I haven't been following it<br>closely myself.<br><br> <a href="http://wiki.osgeo.org/index.php/WMS_Tile_Caching" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://wiki.osgeo.org/index.php/WMS_Tile_Caching</a><br> <a href="http://wiki.osgeo.org/index.php/Distributed_Tile_Caching" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://wiki.osgeo.org/index.php/Distributed_Tile_Caching
</a><br> <a href="http://wiki.osgeo.org/index.php/Tile_Map_Service_Specification" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://wiki.osgeo.org/index.php/Tile_Map_Service_Specification</a><br><br>My thinking is that if they hammer this out it would be nice if the<br>geoquadtree cache format sitting on a web server would adhere to their<br>specification making it directly usable. I don't know enough about this
<br>to be sure if this is reasonable or not.<br><br>Best regards,<br>--<br>---------------------------------------+--------------------------------------<br>I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
warmerdam@pobox.com</a><br>light and sound - activate the windows | <a href="http://pobox.com/%7Ewarmerdam" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">http://pobox.com/~warmerdam</a><br>and watch the world go round - Rush | President OSGeo,
<a href="http://osgeo.org/" target="_blank" onclick="return top.js.OpenExtLink(window,event,this)">
http://osgeo.org</a><br><br></blockquote></div><br>