The County Planning Commission yesterday approved the controversial Alta Mira housing development planned adjacent to Friendly Hills Elementary School in Joshua Tree. The 4-to-1 split decision gives the go-ahead to the 248-unit gated community. Commissioner Paul Smith, representing Morongo Basin, cast the lone opposing vote. He argued that the project violates the spirit and intention of the Joshua Tree Community Plan, that the traffic study conducted for the project was outdated, and that the tortoise studies for the project relied on tainted and out-dated information. Unless an appeal is filed with the County Board of Supervisors in the next 30 days, that decision will be binding.