I am trying to merge several (70 at least) raster files (a digital elevation model, ASTER DEM v2). I am using QGIS and I use the tool "Raster > Miscellaneous > Merge".
I works well and I get the new raster, but the elevation values are not concordant with the values on the original rasters. For instance, there are individual rasters with elevation >2000m, and in the new raster I get values until 1500m.
I have also used "Raster > Miscellaneous > Build Virtual Raster", but the same happens. I have tried as well to merge fewer raster files; it still does not work.
What should I do? Any suggestions?