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Region 3

Notes for region 3 accuracy assessment:

Sampling procedure followed general design. The geographic stratum was created using 15' x 15' grid cells. Primary sampling units (PSU) defined by non-overlapping, interior regions of aerial photographs acquired by the National Aerial Photograph Program (NAPP) were delineated within the stratum. A single PSU was selected from each grid cell, with all PSUs having an equal probability of being selected. The pixels selected within the first-stage PSUs were then stratified by mapped land-cover class, and a simple random sample of pixels was selected independently for each land-cover class. A total of 1125 sample pixels were used for the accuracy assessment.

Only primary land cover label was interpreted from the NAPP photos. No information was collected on alternate land cover class and photointerpretation confidence rating. This lack of the alternate land cover label tends to deflate the accuracy estimates by allowing no adjustment for spatial and thematic uncertainties related to non-mapping procedures.