A Photo's worth 1,000 Topos
On desert scrubland or slickrock, an aerial image may reveal vital navigational clues that don’t appear on topo maps, such as shallow canyons, small knolls, vegetation, and new roads. Take this photo (A) of Davis Gulch, Utah, showing sandstone domes and greenery, none of which appear on the topo (B). Google Maps and Google Earth satellite images are updated more often than USGS maps. Try both services to find the best resolution for your area.
Be aware: Aerial photos can make huge obstacles (like cliffs) appear tiny, so check in with rangers, read trip reports, and plan detours in advance.