|
Hi Jonathan,
Is it possible that QGIS is using the infrared band as an alpha
channel? This might explain the whitening effect, especially in
non-vegetated areas. I would check the Layer properties
Transparency tab to see whether anything is set as the
transparency band. If it is, you could override QGIS by setting a
default style.
Cheers,
Andy
On 02/12/2013 11:53, Jonathan Moules wrote:
Hi List,
I've got a 4 band raster aerial photography (RGBI) that
comprises lots of tiles. I've merged some of the tiles
together with:
gdal_merge
-o 1.tif -of GTiff -co TILED=YES -co BIGTIFF=YES -co
COMPRESS=JPEG -co JPEG_QUALITY=50 -co BLOCKXSIZE=512 -co
BLOCKYSIZE=512 --optfile tiff_list.txt
But the resultant file looks funny in QGIS.
This is what the source file looks like (correct):
This is what the merged file looks like (wrong):
All the shadows are a whitey colour. This doesn't happen
with 3-band (RGB) images.
I've tried comparing individual bands; they all look
different in the 4-band.
However, if I open the four-band in ArcGIS, it looks fine
(both source and original).
Anyone know what's going on? Is it a QGIS bug or is it
doing something "smart"; I can't see anything odd going on
with symbology.
Thanks,
Jonathan
This
transmission is intended for the named addressee(s) only and may
contain sensitive or protectively marked material up to
RESTRICTED and should be handled accordingly. Unless you are the
named addressee (or authorised to receive it for the addressee)
you may not copy or use it, or disclose it to anyone else. If
you have received this transmission in error please notify the
sender immediately. All email traffic sent to or from us,
including without limitation all GCSX traffic, may be subject to
recording and/or monitoring in accordance with relevant
legislation.
_______________________________________________
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
--
Andy Harfoot
GeoData Institute
University of Southampton
Southampton
SO17 1BJ
Tel: +44 (0)23 8059 2719
Fax: +44 (0)23 8059 2849
www.geodata.soton.ac.uk
|
_______________________________________________
Qgis-user mailing list
Qgis-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/qgis-user
