How to make a substraction between two DEM's to obtain heights differences?

Hi everybody. I am trying to use two DEMs derived from Alos PALSAR to identify height differences between them and define possible landslides, using the Fill process and the Raster Calculator in ArcGis 10.3 but the results aren't satisfactory.

What's the height error in a DEM from Alos PASAR with a horizontal resolution of 12,5 m?

Is necesary to do any other process at the DEM's before make the substraction to reduce the inherent height error?

Digital Elevation Models

Landslides

Gáspár Albert

Eötvös Loránd University

Use QGIS Raster calculator (see this link for description: https://docs.qgis.org/2.8/en/docs/user_manual/working_with_raster/raster_calculator.html).

Or:

Use SAGA GIS (comes with QGIS when installing) for DEM raster processing instead of the QGIS commands.

Either way it is recommended to prepare the two DEMs to be in the same coordinate system, and to have the same extent and resolution (resample).

In SAGA you can do this with the Tools panel ->Grid->Tools and then the ->Calculus submenu commands.

For the vertical error I recommend you to search the Google Scholar for published papers using the "Alos PASAR" keyword!