One critical component of the study of landuse change is the testing of level of agreement between pixels of a satellite-derived landuse map and a reference map (produced with authenticated ground information). This comparison remains the veritable approach for checking the degree of correctness of the image analysis task. However, one of the indices developed for scaling through this task is Kappa Index for the assessment of the components of the study. However, scholars such as Prof Gil Pontius of Clark University have repeatedly affirmed that Kappa Index gives grossly inaccurate estimates with misses and other erroneous outputs. My questions is what are the proffered alternatives to Kappa if we have to accept that the index is inaccurate and misleading? How available at the open science level (open source software packages) are these alternatives so as to have inclusive and easily accessible tools for future land change science studies? These answers are needed because some young and early career remote sensing experts are still glued to Kappa.
Thank you for your contributions to this inquiry.
One of the alternatives to Kappa Index is overall user / producer accuracy per class.
Article Explaining the unsuitability of the kappa coefficient in the...
Hi Iman Javadzarin
The word "hidden" in the question was deliberate because it seems researchers especially the early career which I am a member of are still glued to the usage of Kappa Index. As I stated in the supporting text, there are studies which claimed that Kappa Index is actually erroneous with false hits and misses. I can recall "Death to Kappa..... by Pontius and Millones and the recent study by Prof Giles M. Foody of School of Geography, University of Nottingham, UK titled "Explaining the unsuitability of the kappa coefficient in the assessment and comparison of the 2 accuracy of thematic maps obtained by image classification". So, the intent of this question is to bring to the fore the need to use better validation approaches for image analysis. After reading through these materials, I am sure you will have a shift in your paradigm about Kappa Index. Ciao.
Hi Carl Alexander Frisk
Many thanks, got that reference already.
Using an index to indicate the overall change is simple and useful, and it is sure that some info is missed.
Todo índice es util siempre y cuando según la tecnología disponible se puedan resolver problrmas tecnicos.
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