2. ALOS PALSAR
ALOS stands for Advanced Land Observing Satellite, a satellite also known as DAICHI, and it is a Digital Surface Model (DSM) with 30 meters horizontal resolution at global coverage. PALSAR was one of three instruments on the satellite. You may visit their official website at http://www.eorc.jaxa.jp/ALOS/en/index.htm to read all information and technical details about the project.
The data sets are freely available for you to download, with which you may produce smooth and credible DEMs.
There are various ways to get the data from ALOS PALSAR. One way is to go to their website and register as a new user at http://www.eorc.jaxa.jp/ALOS/en/aw3d30/registration.htm. You may follow the overall procedure by confirming your email address and signing in with your password. After registration, you may search for your area of interest and download the data at http://www.eorc.jaxa.jp/ALOS/en/aw3d30/
You may see an exhaustive list of all of their available data at their Dataset Homepage at http://www.eorc.jaxa.jp/ALOS/en/dataset/dataset_index.htm.
One more convenient way to get ALOS PALSAR data, which we tested and recommend, is to visit Vertex, the Alaska Satellite Facility’s data portal for remotely sensed imagery of the Earth at https://vertex.daac.asf.alaska.edu/ (pic 2).
You will have to follow the overall procedure to register and create your new credentials and after that, you may select your area of interest on the map provided, and then select to download the data in ALOS PALSAR format by checking the correspondent box (pic 3).
We did the same thing for the area of Matterhorn and loaded the DEM on QGIS, from which we also created contour lines with 20 meters intervals (pic 04). The results are awesome.