[Qgis-user] map collars
John C. Tull
john.tull at wildnevada.org
Wed Mar 18 15:28:26 EDT 2009
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.
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
> 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
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