Accuracy assessment of airphoto interpretation of vegetation types and disturance levels on winter seismic trails, Arctic National Wildlife Refuge, Alaska
Published By US Fish and Wildlife Service, Department of the Interior
Issued over 9 years ago
Summary
Description
An accuracy assessment was conducted to evaluate the photointerpretation of vegetation types and disturbance levels along seismic trails in the Arctic National Wildlife Refuge. A sample of 200 of the 4914 photointerpreted points were visited to obtain ground information. Determinations of vegetation types and disturbance levels on the ground were compared with photointerpretations, and errors were divided into three categories: cutpoint errors between closely related classes, definition errors where a more detailed definition was needed in the key and misclassification errors which were either incorrect application of the key or exceptions to the key. The accuracy of interpretation of vegetation types was 75. Eighteen percent of all points were wrong due to cutpoint errors, 3 due to definition errors, and 5 due to misclassification errors. Most cutpoint errors were due to small differences in estimates of shrub cover, moisture or microrelief. The accuracy of disturbance levels was 66. Most errors 29 of all points were from trying to discriminate between closely related classes that were often difficult to differentiate on the ground. Nine definition errors resulted in suggested improvements to the key. Omission and commission errors for disturbance levels were equal indicating that the overall distribution was representative of what actually existed on the ground. Therefore, photo interpretation proved a useful tool for evaluating the extent of disturbance over a wide variety of sites on the coastal plain.