Project .tif file containing DEM data

[Xavervon_Beckerath1]

I'm working on a project for which I need data from different sources. I got satelite images from the Sentinel mission which are already in the appropriate spatial reference when dowloaded, in my case UTM26. My elevation model is from the ArcticDEM project and all downloadable files are using "Stereographic_North_Pole", independently from the location. I'm having trouble changing this to UTM26. My research suggest that "project" is the tool I need but this one does not let me chose my elevation data (.tif).

I'm pretty sure the answer is easy but I was not able to find a solution to this.

[DanPatterson_Retired]

I would suggest using the Project tool (not Define Projection!) to project the stereographic file to a geographic coordinate system (ie GCS WGS84 or similar), then find and clip out the longitudinal range that encompasses UTM26.  Once you have that slice, Project it to a new file again.  Your stereographic projection may cover the whole north pole, ie longitudes from -180 to 180.  But UTM is only a 6 degree slice of it, which accounts for the need to slice the extra bits off

[Xavervon_Beckerath1]

Both data sources allow you to download specific tiles of your location, that means I already got the "slices" I need. ArcMap previews these files correctly (depending on the file which was imported first). However, clipping the exact study area leads to errors, this is why I was trying to change the projection of the elevation model.

I would like to project a new file but the tool does not allow me to take the .tif. The file is not available throught the file browser of ArcMap.

I hope I understood your instructions.

[DanPatterson_Retired]

Does that mean you can't work with both files, saved on your local machine? That is what I would resolve first