I've read in several papers that in order to do a better land cover / land use identification with Landsat images, it is better to project them on a DEM and ortorectificate then.
When I read the Landsat 8 images specifications, I see that they are already ortherectified.
So my question is : do I need to do this step, or can I use Landsat image "as is" ?
Would the response be different for Landsat 5/7 and Landsat 8 ?
Thanks in advance.
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