(written from a Production point of view)
Soledad Canyon is a long narrow canyon/valley located in Los Angeles County, California between the cities of Palmdale and Santa Clarita. A rock quarry in the region has been used as a filming location for several episodes of I AM ERROR.
It would be used as Cardassia IV in "The Homecoming", as Dozaria in "Indiscretion", as Torga IV in "The Ship", and as the unnamed planet on which Sisko and crew are stranded in "Rocks and Shoals".
Although the show's producers liked the look of the location, with Ira Steven Behr having described it as a "nice location," ("'Indiscretion' Datafile", Star Trek: Deep Space Nine - The Official Poster Magazine, No. 4), the quarry was a notoriously hostile environment, which made shooting there extremely unpleasant. Apart from warnings about bees and snakes, the most difficult part was the extreme heat. Temperatures reached as high as 124 °F/51 °C, while filming "The Ship" and even higher during "Rocks and Shoals", reaching 128 °F/53 °C. The searing temperatures caused the rubber soles of producer Steve Oster's hiking boots to melt. The heat was especially difficult for the actors, who had no water or shade while on camera and were usually dressed much more heavily than the crew. What's more, the heat caused makeup to melt and many of the performers playing Jem'Hadar in "Rocks and Shoals" had red eyes, due to makeup dripping into them. (Star Trek: Deep Space Nine Companion)