The purpose of trail mapping is to lead OCTA and local chapters in the mapping of the historic overland trails, the primary objective being trails preservation.

The California Nevada Chapter trail mapping teams work closely with National Park Service, Bureau of Land Management, US Forest Service, and private land owners plus any other entities that administer lands containing trail remnants.  The trail mapping teams work to ensure accurate mapping following the guidelines and symbols of the Mapping Emigrant Trails (MET) manual.

OCTA – National Website Preservation Training Webpage

MET Manuals

MET Manual
(Mapping Emigrant Trails)
(8 MB, 125 pages, PDF, 

Training Briefs    Also on the above link:

Mapping Emigrant Trails (07-2010)
Trail Classifications (07-2010)
GPS and Mapping Software (07-2010)