This report outlines a protocol for assessing the thematic accuracy of large-scale ecosystem mapping. The protocol presents a statistically unbiased approach to evaluating the acceptability or accuracy of the mapping. The thematic content of randomly selected map polygons, or small areas, is assessed by various means, with the methods varying in precision & objectivity. The protocol requires the development of a sampling plan that articulates decisions about such matters as protocol level, sample size, assessment method, and target error. The approach outlined in this protocol provides a means of obtaining some overall, statistically valid scores to rate the accuracy of predictive ecosystem mapping, terrestrial ecosystem mapping, or other ecosystem maps. The results can be used as a component of quality assurance or for presenting statistics on the accuracy of mapping.

This paper presents a protocol for assessing the predictive accuracy of thematic maps. Although developed during the Cariboo Predictive Ecosystem Mapping (PEM) pilot, the Canim Lake PEM operational prototype, and the Quesnel PEM to test the accuracy of predictive ecosystem maps, this protocol is applicable to many thematic maps. The Protocol for Accuracy Assessment of Ecosystem Maps (Meidinger 2003) incorporates many of the concepts presented here, but recent work done on the Canim Lake and Quesnel PEMS suggests that a more detailed operational protocol is needed to ensure the integrity of the data collected. In addition to detailed instructions and specifications for data collection, this paper describes a staged sampling protocol designed to minimize the sampling cost required to attain a specified level of confidence in the assessed accuracy.