This question concerns work-flow rather than specific methodological problems.
I will be using GRASS to classify Landsat 8 images to create a vegetation map for a study site that happens to fall over 2 separate Landsat scenes.
I would really appreciate some advice about which route to take and I'm not able to find any other information about this elsewhere:
1.) Should I FIRST find a way to combine the 2 scenes together (which presumably would require combining the 2 scenes of each channel separately - would that be right?), and then cut out the small area covered by my study site and THEN start the classification process.
2.) Should I conduct image classification on the 2 adjacent Landsat scenes separately and then combine right at the end? (Although I'm worried this will take much longer, not to mention use up more memory - the study site I am working with is only 1400 km2)
N.B. I am using a Mac (Mavericks OSX) and have access to both QGIS 1.8.0 and ArcView 9.2 to conduct any manipulation on this Geotiff files.
Thank you very much for your time and advice!