Uncertainty estimation for map-based analyses
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In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest and Southern Research Stations: 637-646
Traditionally, natural resource managers have asked the question, “How much?” and have received sample-based estimates of resource totals or means. Increasingly, however, the same managers are now asking the additional question, “Where?” and are expecting spatially explicit answers in the form of maps. Recent development of natural resource databases, access to satellite imagery, development of image classification techniques, and availability of geographic information systems has facilitated construction and analysis of the required maps. Unfortunately, methods for estimating the uncertainty associated with map-based analyses are generally not known, particularly when the analyses require combining maps. A variety of uncertainty methods is illustrated for map-based analyses motivated by the threat of the emerald ash borer (Agrilus planipennis Fairmaire) to the ash tree (Fraxinus spp.) resource in southeastern Michigan. The analyses focus on estimating the uncertainty in forest/nonforest maps constructed using forest inventory data and satellite imagery, ash tree distribution maps constructed using forest inventory data, and estimates of the total number of ash trees for a selected region obtained by intersecting the two maps. A crucial conclusion of the study is that spatial correlation, an often ignored component of uncertainty analyses, made the greatest contribution to uncertainty in the estimate of the total number of ash trees.
KeywordsEmerald ash borer; forest classification; forest inventory; logistic model; Monte Carlo simulation; spatial correlation.
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McRoberts, Ronald E.; Hatfield, Mark A.; Crocker, Susan J. 2010. Uncertainty estimation for map-based analyses. In: Pye, John M.; Rauscher, H. Michael; Sands, Yasmeen; Lee, Danny C.; Beatty, Jerome S., tech. eds. Advances in threat assessment and their application to forest and rangeland management. Gen. Tech. Rep. PNW-GTR-802. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest and Southern Research Stations: 637-646.