I realize this goes into other software on a qgis list, but I wonder
with GDAL or GRASS one can accomplish this.
It is really a raster clip that would work well, especially if the
next step is mosaic'ing the rasters. Are these quad maps?
Mark
On Mar 18, 2009, at 3:28 PM, "John C. Tull" <[email protected]>
wrote:
Although, this approach can be problematic if white is important for
properly displaying the map information. E.g., USGS topographic maps
use a white background for the map and a white collar. My solution
was to hand select the collar in Gimp, make it a unique color
(magenta or something), then apply the transparency to that color.
This is not fun if you have many maps to work with.
John
On Mar 18, 2009, at 4:17 AM, Paolo Cavallini wrote:
Chris h ha scritto:
No apology necessary. Map collars are the white borders around
maps that are
typically distributed from governmental sources in raster format.
In order to
stitch or glue charts together you need to remove the collars.
(white area)
Oh, that can be easy: for displaying purposes, just set the white
value
to null, in the raster properties dialogue. If you want to
permanently
set the white to NULL, you can use gdal for this.
All the best.
--
Paolo Cavallini: http://www.faunalia.it/pc
_______________________________________________
Qgis-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-user
_______________________________________________
Qgis-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-user
_______________________________________________
Qgis-user mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-user
