[Qgis-user] Gdal Clipper plugin

[Michael Kimmerly]

The gdal_warp -clipper plugin in Qgis appears to be a real life-saver for me
in my use of Qgis in doing NDVI analysis in agriculture where I need to clip
my data to a particular farm or field that may be quite irregular in shape.
However, I am having difficulties getting the plugin to properly trim to the
extent that I want to end up with.

My process is:

1. I am loading a landsat scene for my data.
2. Creating a shapefile layer and digitizing a polygon of the area that I
want to analyze. 
3. Select the polygon and save as a separate shapefile.
4. Perform the clipper function on the landsat raster using the saved
polygon shapefile as my mask.

Not sure if step 3 is necessary but want to make sure the mask is limited to
only the polygon that I digitized. Also the mask polygon may come from an
already existing shapefile that may have been gps'd or previously digitized
from some other source.

The resulting raster is clipped to the polygon but the extent is still the
original landsat. From gdal documentation appears that the -crop_to_cutline
needs to be included in the plugin. Am I correct in this or am I missing
some step?

Thanks for any help.