I've tried to look here:
But it's not clear to me. Also I don't understand why über-queren should literally translate as over crossing.
Can you help me?
Überqueren requires that you cross something that's physically located beneath you. Take
Die Straße überqueren (crossing the street)
Im Flugzeug den Kanal überqueren (crossing the Channel by plane)
Queren describes a traversal where the movement is roughly perpendicular to a (often implicitly) contextually defined preferred orientation of what is being crossed.
Die Nordwand queren [alpinism] (traversing the north face).
- The contextual orientation is vertical while the mountaineer climbs from one side of the face to the other, though often not strictly keeping his altitude.
Ein querender Fußgänger (a pedestrian crossing our path).
- The contextual orientation is your own bearing.