When you get this all working, please post a description of the final outcome in the grass wiki.
Thanks,
Jerry
---- Original message ----
Date: Wed, 19 Dec 2007 15:16:10 +0200
From: Craig Leat <craig@pid.co.za>
Subject: Re: [GRASS-user] Working with a large number of maps
To: Glynn Clements <glynn@gclements.plus.com>
Cc: grass-user@lists.osgeo.orgGlynn Clements wrote:
Craig Leat wrote:
I have 139 high resolution images, which I need to use as a background map
for some digitizing work.
How do the individual maps relate to the overall region?
If they are (approximately) tiles, I would suggest using a
hierarchical approach, patching groups of adjacent tiles into larger
tiles, then patching the larger tiles together, so that each r.patch
operation has relatively few maps, and the earlier stages have
relatively small regions.The total time taken by r.patch is roughly proportional to the total
number of cells in the region multiplied by the number of input maps,
so the combination of a large region and a large number of maps will
be slow.Thanks for the advice Glynn. The images are tiles and the filenames
follow a regular pattern, so I am able to patch blocks together quite
easily with a simple script. I included lots of echos in the script and
now I even have verbose messagesThe script is running right now and making good progress...
Craig
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