make a list of locations
I use a portal to list all the locations where my books are stored. When I look at a particular book I can see all of the locations where it is stored. I want to make a list of all of my locations. So I can see which locations have been added to my inventory. Before I started using this portal I used to use a location field. I added several locations to this field. I am in a transition phase where most of my locations are in the old location field and where all of the new titles are added to the portal.
What would be the best way to make a list that shows the locations from the portal and the field in a list, where each location is listed only once, if possible, in ascending order?