polygonqgisrastervector
QGIS is trying to create a polygon for the Raster image using Polygonize (Raster -> Vector).
My Raster Data is a satellite image, but when I Polygonize it, polygon is generated in each pixel and appears in grid form. This problem takes a lot of time to process.
I'm going to create a polygon that fits the overall image size.
Give me a tip.
For GRASS GIS Zonal statistics, see http://grasswiki.osgeo.org/wiki/Zonal_statistics
It looks as if you want to use "v.vect.stats": count points in areas, calculate statistics from point attributes (needs GRASS 7).
Thank you very much for your help.
I was trying to use SERVAL but I couldn't find any example of application. What I managed to do in order to make the black patches to dissapear was this:
Not sure if this was what you were suggestion. I tried to use the poligonized with these layer but the error message was the same.
Best Answer
You can use the Extract Layer Extent tool from the processing toolbox:
The output will be as expected: