SOUTH DAKOTA TECHNICAL GUIDE NOTICE SD-325
SECTION I – REFERENCE LIST - TECHNICAL NOTES – TECHNOLOGY – PAGE 11 OF 12 OCTOBER 2011
Appendix A
Official Natural Resources Conservation Service (NRCS)
Policy in South Dakota (SD) for
Using Trimble GeoXT 2008 Global Positioning System
(GPS)
Unit to Certify Conservation Practices
PROCEDURES
Background
The Trimble GeoXT 2008 series GPS units have shown to have high level of
accuracy for geographic information system (GIS) data collection. Trimble units
properly used by trained personnel can meet current NRCS spot-checking
tolerances for practice certification.
Area Measurements
Trimble GPS units can be used to measure any area for practice certification as it
has reliable accuracy within one to three meters when the Positional Arelution of
Precision (PDOP) is at or below 5.0. The GeoXT is geared toward maintaining
precise GIS databases by delivering submeter accuracy.
Length Measurements
Trimble GPS units can be used to measure any length for practice certification on
slopes less than 15 percent provided the accuracy level calculated by the GPS
unit has a PDOP at or below 5.0. If slopes exceed 15 percent for a portion of the
measurement, the steeper slope lengths must be measured by conventional
methods, such as tapes or measuring wheels.
Verification of GPS Data for Practice Certification
All area and length measurements obtained from the Trimble units for practice
certification must be downloaded into Common Computing Environment (CCE)
approved GIS software for verification of the proper location of the conservation
practice. Trimble data (position points) used for practice certification will be
stored in a Customer folder in Customer Service Toolkit (CST) for that
cooperator. When CST and Trimble equipment are used to certify a
conservation practice, the Conservation Practice Certification Template shall be
used to document certification of all conservation practices.
Use of Digital Orthophotography or Other Georectified Imagery for Practice
Certification
Areas that are very WELL-DEFINED (visually) on Digital Orthophotography or
other georectified imagery can be digitized and measured using CST for practice
certification. The view scale shall be 1:7920 (1 inch = 660 feet) or less.
To Next Page
Loading...