[Qgis-user] Raster

[Nicolas Cadieux]

Hi,


Another way is to add an alpha band to the image.  I generally use GIMP 
to do this.  If the Georeferencer sees and alpha band, then, the border 
will use this band.


Nicolas

On 2022-05-24 7:25 a.m., Richard McDonnell via Qgis-user wrote:
>
> Easiest way I can think of doing what you want is to create a VRT of 
> the three raster’s.
>
> *Raster*è*Miscellaneous* è*Build Virtual Raster*
>
> When you do this set the *Nodata value* to 0 (the default transparent 
> value form the Georeference Tool)
>
> This should create a merged raster for you and allow you to use the 
> correct transparency value.
>
> Hope this helps,
>
> Richard
>
>
> ——
> Richard McDonnell MSc GIS, FME Certified Professional
> /FRM Data Management/
>
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> ——
> MSc GIS, FME Certified Professional
>
> ——
> Oifig na nOibreacha Poiblí
> Office of Public Works
>
> Sráid Jonathan Swift, Baile Átha Troim, Co na Mí, C15 NX36
> Jonathan Swift Street, Trim, Co Meath, C15 NX36
> ——
> M +353 87 688 5964 T +353 46 942 2409
> https://www.opw.ie
>
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>
> *From:*Qgis-user <qgis-user-bounces at lists.osgeo.org> *On Behalf Of 
> *Lazanu Ciprian-Catalin via Qgis-user
> *Sent:* 24 May 2022 11:53
> *To:* Uwe Fischer via Qgis-user <qgis-user at lists.osgeo.org>; Uwe 
> Fischer via Qgis-user <qgis-user at lists.osgeo.org>
> *Subject:* [Qgis-user] Raster
>
> Hello,
>
> I georeferenced three maps ... all good, quite easy by using points 
> from map canvas. When my map was ready it has a black border (image 
> 1). This is solved by ~Custom transparency options~, and a black 
> border disappears. But this solution is just temporarily, because if I 
> close and reopen ... that raster has again a black border. I want to 
> merge the three maps in one, but it does with a black border between 
> maps.
>
> A solution to this annoying problem?
>
> Thank you
>
> https://drive.google.com/drive/folders/1qM1_TeFUng9-xyRXRQCuMrEMwxFeJV7n?usp=sharing 
> <https://drive.google.com/drive/folders/1qM1_TeFUng9-xyRXRQCuMrEMwxFeJV7n?usp=sharing> images
>
> Meet Google Drive – One place for all your files 
> <https://drive.google.com/drive/folders/1qM1_TeFUng9-xyRXRQCuMrEMwxFeJV7n?usp=sharing>
>
> Google Drive is a free way to keep your files backed up and easy to 
> reach from any phone, tablet, or computer. Start with 15GB of Google 
> storage – free.
>
> drive.google.com
>
>
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-- 
Nicolas Cadieux
https://gitlab.com/njacadieux
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