These distances are exact, but are based on a straight line from point to point. Actual walking distances will be slightly longer.
We have been in Santerem yesterday (13.4.2019) and discovered that this albergue is closed!
I do not know if it is closed just in low season but it seems that it is closed always.
We went to the Santerem Hostel instead. 15€/Person incl breakfast. Comfortable beds and hot shower. Very recommendable :)