[gdal-dev] Mosaicking Orthos

[Zoltan Szecsei]

On 2011-02-16 12:20, Zoltan Szecsei wrote:
> Hi All,
> I've built a vrt with 176 images.
>
> I now need to mosaic this whole area into roughly 5 x 5 ortho images.
>
> How can I force the white edges into background of the overlapping 
> orthos?
> I'm a little cautious of simply (finding a way to) making "white" 
> transparent as it is only the white on the edges that need to be 
> backgrounded.

Hi again,
Since the above post, I have tried different ways to set nodata, but to 
no avail - I still get the white edges:
(see jpeg sent with my original post)

gdalbuildvrt -addalpha -hidenodata -input_file_list files 
177_untiled_orthos_nodata.vrt
gdalbuildvrt -srcnodata "0 0 0"  -addalpha -hidenodata -input_file_list 
files 177_untiled_orthos_blk.vrt
gdalbuildvrt -srcnodata "255 255 255"  -addalpha -hidenodata 
-input_file_list files 177_untiled_orthos_white.vrt

How should I be masking out the nodata (or even white pixels) so that 
when I mosaic a bunch of tiffs together, I dont get the white stripes in 
the resulting image?

Using GDAL 1.7.3, released 2010/11/10 on Ubuntu 10.04
Viewing with Quantum GIS - 1.6.0-Trunk on Ubuntu 10.04 (same box).
...but running the whole lot in xterms with Xming & putty from my 
WinVista box.


Regards,
Zoltan




-- 

===========================================
Zoltan Szecsei PrGISc [PGP0031]
Geograph (Pty) Ltd.
P.O. Box 7, Muizenberg 7950, South Africa.

65 Main Road, Muizenberg 7945
Western Cape, South Africa.

34° 6'16.35"S 18°28'5.62"E

Tel: +27-21-7884897  Mobile: +27-83-6004028
Fax: +27-86-6115323     www.geograph.co.za
===========================================



-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 10.0.1204 / Virus Database: 1435/3446 - Release Date: 02/15/11