It's new to us anyway, but we don't own a dog. Perhaps this is old news to those of you who do.
 
Judi met someone who has both a dog and a GPS. They enjoy taking long day hikes in the desert. When they go out and back on the same route, on the way out, they mark a waypoint wherever poochums has to "take care of business". Then, using the marked waypoints,  they break out the plastic bags at the appropriate spots on the way back, minimizing the time and distance they need to carry those canine "caches".
 
Brought to you as a public service by...

Steve
Team Tierra Buena