[GRASS-user] Virtual Mosaic import with r.external

[Jeshua Lacock]

Hello,

I was following along the Large raster data processing wiki with great interest:

http://grasswiki.osgeo.org/wiki/Large_raster_data_processing


My question is, when tiles are merged in GRASS using a virtual mosaic created with gdalbuildvrt, will transparent map collars be preserved?  I see the man page for r.external talks about the requirement to build a mask or use r.mapcalc, but I don’t understand how I would apply that to a virtual mosaic. Is it possible?

Would a certain file format handle transparent border collars better than others?

Note that I already have all my tiles as GRASS rasters in my current location, alas I tried using r.patch running in parallel for the job first but it pretty much choked on the task. My attempt was terminated due to a power outage after running several weeks trying to create around 0.5 terrapixel mosaic.

Any suggestions how to best build a mosaic would be super appreciated! 


Thanks,

Jeshua Lacock
Founder/Engineer
3DTOPO Incorporated
<http://3DTOPO.com>
Phone: 208.462.4171