let me try to summarize it:
- if you have only two datasets and both are well geocoded,
collocation
is sufficient. - if you deal with multiple rasters and all are well geocoded, you can use
create stack
. - if you deal with data acquired from different sources or angles or you have terrain-induced distortions (often the case for radar data) you need
coregistration
to match the rasters precisely at the sub-pixel level. This is also required for interferometric analyses
Please, anyone feel free to comment if I missed an important point.