Photo plot bias.

Robert B. Pope; Bijan Payandeh; David R. Paine

Treesearch

Photo plot bias.

Informally Refereed

Authors:

Robert B. Pope, Bijan Payandeh, David R. Paine

Year:

1972

Type:

Research Paper

Station:

Pacific Northwest Research Station

Source:

Res. Pap. PNW-RP-145. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p

Download (PDF 1.58 MB)

Download (PDF 1.58 MB): https://research.fs.usda.gov/download/treesearch/26267.pdf

Abstract

The photo intensity, or number of aerial photos per unit of land surface, was examined for six Agricultural Stabilization and Conservation Service photo projects in western Oregon and Washington. On each of the six projects, lands that were primarily nonforest were found to have more photos per unit of area than did the forest lands. Overall, photo intensity averaged 4.1 percent greater on nonforest than forest areas. This suggests a serious source of bias in any forest inventory using photo plots with an equal number of plots per photo. There was no evidence that this difference in photo intensity was associated with elevation differences. The problem can be avoided by transferring plot locations from maps to photos.

Keywords

aerial photography, forest surveys, photography

Citation

Pope, Robert B.; Payandeh, Bijan; Paine, David R. 1972. Photo plot bias. Res. Pap. PNW-RP-145. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p