[Qgis-user] Trouble in georeferencing

[Nicolas Cadieux]

Hi,

There are a few ways to fix this.  One way is to specify the no data 
value in the original file. The black area around the image will take 
that no data value. (This is what I recommend if your data is not 8 bit 
data with value between 0 and 255. This way, you can select a no data 
value (like -32768) that will not show up elsewhere in the image.

The second way is to go into the georeferencer Transformation 
Parameters.  Then select Use 0 for transparency when needed.  This is Ok 
in most cases but if you have 0 in your image, then those areas will 
disappear also.

The other way is to open the image in GIMP, then, left click on the 
layer and select "add Alpha Channel" and then save the file. This will 
add a new band to the file and the area around the file will be transparent.

I you have images that have this black band, you can also add no data 
values in the layer properties.

Hope this helps

Nicolas


On 2022-01-30 7:25 a.m., Akanksha Chugh wrote:
> There appears black area around the image and also it is stretched out 
> and blurred.
>
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-- 
Nicolas Cadieux
https://gitlab.com/njacadieux