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U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Area Determination and Geospatial Support

Area-determinations, positioning, navigation, and mapping are just a few of the many aspects of forestry requiring spatial (geographic) information. The Forest Products Measurements group, Forest Management Service Center (FMSC). Fort Collins, Colorado, is responsible for determining the methodology to correctly locate and determine the size of timber units. Sufficiently accurate areas are often required to calculate volume correctly or to determine area needs for forest management.

Geospatial standards also assure operations with resources like remote sensing, field ground locations, digital mapping, and legacy resources are properly registered with each other to sufficiently determine the requirements for timber cruising and associated forest management operations.


TwoTrails is a timber cruising and timber sales admin surveying package. It is maintained and developed by the Forest Management Service Center. Though it is specifically written for USDA forestry personnel, it is freely available to anyone. Many of the program capabilities are shared below:

  • Manages all surveying methods approved by USDA Forest Service Handbook, FSH 2409.12, Chapter 50, Area Determination.
  • Real-time GPS surveys:
    • GPS Walk (Breadcrumb)
    • GPS Angle Point (Take5)
  • Real-time surveys:
    • Direction Distance Traversing
    • Radial (example: Island Exclusions)
    • Corridors (example: Hazard Tree)
  • Combined use of multiple survey types:
    • GPS surveys
    • Digitized Information (Shape Files, KML/KMZ, GPX, CSV)
    • Remote sensing information
  • Create Grid (Sample) Point sand Navigate to them
  • Can use .ttx (Android) and legacy .tt2 (TwoTrailsV2) projects
  • Exports:
    • GIS Shape Files
    • KMZ and GPX
    • Project Status and Information
    • CSV’s (Points, Polygons, Metadata, NMEA Information, etc..)
  • Automatically calculates area-error for comparison with handbook standard
  • Live visual mapping with point creation and modification
  • Full support to Forest Service personal via Forest Service Management Center (Support to others is available as well when resources allow)


  • TwoTrails has both Android and Windows Mobile applications with supporting Windows PC support for each. TwoTrails is free.

TwoTrails Software registration and download page for all versions, including the guides…


  • Training is available for using TwoTrails in timber cruising exercising the handbook allowances to efficiently preform required surveys for sales, management and map/GIS preparations.
  • The user guides that can be downloaded with the software have proven to be intuitive and many cruisers need nothing else to do basic work.
  • Virtual classes can be arranged. Small groups of less than 8 students is preferred, enabling attention to each student and the uniqueness of the local forest. One student is a champion who has used the software or who will prepare with the instructor before the class. For more information, contact contact Gary Boyack (