Several GPS based Apps are available which some orienteering clubs set courses on. They are a way to set training without needing to put out control makers. They rely on mobile phone GPS signal which is OK in urban races and parks, but will struggle under tree cover.
MapRun
iorienteering
GPS Orienteering
http://www.hippsomapp.se/?lang=en
Other useful Apps
What 3 words
This App divides the world into 3 x 3 metres squares and assigns three words as the unique identifiers to each square.
