Re: [gdal-dev] Using the alpha channel to mask parts of an image

2011-09-22 Thread Frank Warmerdam
On 11-09-22 05:00 AM, Jan Hartmann wrote: Hi, I have a set of unreferenced RGB images with black borders I want to cut off. I do this by adding a fourth alpha band to the image when warping it, and filling this with 255 within the data rectangle, and 0 outside, using gdal_rasterize ( I have the

[gdal-dev] Using the alpha channel to mask parts of an image

2011-09-22 Thread Jan Hartmann
Hi, I have a set of unreferenced RGB images with black borders I want to cut off. I do this by adding a fourth alpha band to the image when warping it, and filling this with 255 within the data rectangle, and 0 outside, using gdal_rasterize ( I have the exact georeferenced boundaries of the