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Thematic map accuracy is a measure of correctness that can be defined as the degree to which the attributes of a map agree with ground-truth datasets. It is typically based on a sample of reference sites to which the "true" category (determined by ground thruthing or by the interpreting high resolution imagery) is compared to the one in the map through a confusion matrix. A variety of sampling designs such as simple or stratified random designs can be used to select these references sites. However, in order to calculate the accuracy indices and their associated uncertainty, the type of sampling design used should be taken into account. The confusion matrix enables also users to carry out an adjustment of category´area estimator and avoids the possible measurement bias associated with map's commission and omission errors. This suite of tools (QGIS plugin, DINAMICA EGO submodels and R scripts) computes the overall, user and producer accuracy estimates along with their confidence intervals and provide an error-adjusted area estimator.
More information is available at Mas, J.F., A. Pérez-Vega, A. Ghilardi, S. Martínez, J. Octavio Loya-Carrillo, and E. Vega, "A Suite of Tools for Assessing Thematic Map Accuracy," Geography Journal, vol. 2014, Article ID 372349, 10 pages, 2014. doi:10.1155/2014/372349
Financial support for this research was made possible by SEP- CONACyT (project no. 178816).
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DINAMICA Ego |