[mapguide-users] GDAL Provider and Image Catalogs?

[Andy Morsell]

Shreepad,
Much of this was resolved for me with the ability to use tile index config
files with FDO 3.2.3 and MGOS 1.2.  See this page for information on
Creating Tile Index Config Files -
http://trac.osgeo.org/fdo/wiki/FdoGdalNotes.  There are still some
performance issues, but this has made it usable for me in the instance I
described below.  However, I have not attempted to use raster as a base
layer in this case since performance without them was acceptable, so I'm not
sure if those issues still exist.


Andy Morsell, P.E.
Spatial Integrators, Inc.
http://www.SpatialGIS.com

-----Original Message-----
From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of shreepad
Sent: Tuesday, January 22, 2008 11:09 PM
To: mapguide-users at lists.osgeo.org
Subject: Re: [mapguide-users] GDAL Provider and Image Catalogs?


Hi
i have a exactly same problem. GDAL does not work at all it gives me all
kinds of crashes and with mrsid files its really slow. With tiff images in
one folder it crashes MGOS 


Please advice 

shreepad



Andy Morsell wrote:
> 
> Hi,
> This is mostly directed at Frank and other FDO folks.  I am needing to
> implement MGOS for a client using some publicly available aerial photos
> which we plan to expose via base layers and then pre-render via a tile
> rendering script.  In this case, there are approximately 1300 MrSID images
> that make up a County worth of data.  The maximum image size is 3 MB. 
> When
> defining a data connection using the GDAL FDO provider that points to this
> folder, I do not have favorable results.  I can repeatedly get MapGuide
> Server to crash while this layer is rendered and the crashes occur during
> the GDAL reads of the images, but never while reading the same image and
> never with very meaningful debug information.  This is using MGOS 1.1.0
> and
> FDO 3.1 since 1.2.0 beta 1 currently does not work with the single
> threaded
> GDAL provider.  Along those lines, it's a shame to see a quad processor
> server utilizing only 25% of its potential horsepower because of single
> threading..
> 
> While watching what is happening while running MapGuide Server in
> interactive and debug mode, it is apparent that the GDAL provider tries to
> open every image in the data connection folder for each map render.  This
> happens even if the current view is zoomed to a level where only 4 images
> need to be opened.  This is obviously very inefficient and probably part
> of
> the crashing problem.  A solution to this would be to use an image tile
> catalog index so that only the images needed for the view are accessed.
> 
> I see that there was some talk on this subject, mostly in the FDO mailing
> list, back in January.  But, has this moved forward at all and can we
> expect
> to see image catalogs supported by they GDAL provider in the near future?
> If so, when?
> 
> By the way, I started using FWTools to attempt to mosaic these images, but
> quickly discovered that a resultant Erdas image would have been in the 200
> GB range.
> 
> Thanks for any insight into these matters.
> 
> Andy Morsell, P.E.
> Spatial Integrators, Inc.
> http://www.SpatialGIS.com
> 
> 
> _______________________________________________
> mapguide-users mailing list
> mapguide-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/mapguide-users
> 
> 

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