Confusion Matrices Help Prevent Reader Confusion: Reply to Bechtel, B., et al. A Weighted Accuracy Measure for Land Cover Mapping

In Remote Sensing
Volume (Issue): 12 (11)
Peer-reviewed Article

Land use/land cover (LULC) maps are now being used across disciplines for many different types of applications, e.g., to analyze urban heat islands or rainfall-runoff dynamics. Traditional map accuracy metrics are limited in this regard, as they only assess LULC map thematic accuracy. In reality, some types of misclassification lead to larger estimation errors for these specific applications. In a previous study, we developed a new map accuracy metric (referred to here as “JJ19”) to assess the accuracy of local climate zone maps for urban microclimate analysis. In the previous work, we also attempted to reproduce another metric (weighted accuracy (WA)) proposed for this purpose, but misinterpreted it due to a lack of methodological information available (principally, the lack of a confusion matrix to demonstrate how WA was derived). We sincerely thank the authors of Bechtel et al. 2019 for providing more information on WA in response to our previous study and are happy to report that we found that the metric is now both reproducible and valid. On the other hand, we found some other aspects of Bechtel et al. 2019’s study to be inaccurate, particularly their claims regarding the suitability of the JJ19 metric. Finally, we made a minor improvement to the JJ19 metric based on Bechtel et al.’s comments.