I know with some passable approximation where my home is and where i go in vacationbecause i like looking at maps and getting an idea. however, I would never be able to pinpoint a location i've been to once in the middle of a featureless desert.
However, now that I think about it, there is something that don't work. girard expected soon to come looking for the gate. and soon knew that the gate was in windy ccanyon, and even if he had no idea on where the canyon was, he would have had no problem asking around. And once he was in the canyon, he may have remembered the path - big maybe here. He probably would not have been able to remember exactly that at some point there was a passage where now is plain rock, but he could have brought some cleric with true sight. So soon may have been able too find the gate again if he had come looking for it in person. But since the name windy canyon was not passed to the paladin gang, they are unable to locate the gate without soon. I just don't understand how girard expected it to fool soon that way.
the best explanation I can think of is that soon never heard the name windy canyon in the first place. without that name, he only knew the gate was in a canyon complex somewhere in the desert.
Still it should have been possible for soon to locate it. there shouldn't be too many canyon complexes of that complexity in the desert. And only one of them has some divination-blocking spell going on.
Long story short: even if soon did not knew the coordinates, the informations he had - that the gate was in a canyon complex in the desert, and roughly a path into that complex - would have been enough for him to track down the gate, with time, some lackeys and a few gather information checks.