The Effect of Positional Errors on the Accuracy of Estimates in Guided Transect Sampling
Abstract:Guided transect sampling was recently proposed as a method for sampling sparse and geographically scattered populations if auxiliary data with high spatial resolution are available prior to the inventory. In practice, a surveyor will use GPS to follow predetermined survey lines. However, the surveyor will never be able to follow the lines exactly, and thus the accuracy of estimates is likely to be affected. The aim of this article was to study the loss in accuracy of estimates in guided transect sampling due to errors in navigation. The evaluation was made through Monte-Carlo simulations in different simulated forest types. The auxiliary data were considered to be volumes of deciduous trees, and the variable of interest the abundance of an indicator species connected to deciduous trees. To describe the surveyors' movements along the survey lines, a Brownian bridge process was proposed and evaluated with field data. The results from the study indicate that errors in navigation only have a minor effect on both bias and standard errors of estimates of the population total. The bias was not higher than 2.9%, and the increase in standard error not higher than 3.2 % in any forest type. FOR. SCI. 48(1):101–110.
Keywords: Brownian bridge process; GPS-navigation; environmental management; forest; forest management; forest resources; forestry; forestry research; forestry science; multiresource forest inventory; natural resource management; natural resources; strip surveying; two-stage design
Document Type: Miscellaneous
Affiliations: 1: Assistant Professor in Natural Resource Inventory Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, S-901 83 Umeå, Sweden, Phone: +46 90 7866838; Fax: +46 90 778116 Anna.Ringvall@resgeom.slu.se 2: Professor in Forest Inventory Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, S-901 83 Umeå, Sweden, Phone: +46 90 7865837 Goran.Stahl@resgeom.slu.se 3: Assistant Professor in Forest Management Planning Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, S-901 83 Umeå, Sweden, Phone: +46 90 7865831 Tomas.Lamas@resgeom.slu.se
Publication date: 2002-02-01
- Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
Forest Science is published bimonthly in February, April, June, August, October, and December.
2015 Impact Factor: 1.702
Ranking: 16 of 66 in forestry
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