Applications of hyperspectral imaging (HSI) to the quantitative and qualitative measurement of samples have grown
widely in recent years, due mainly to the improved performance and lower cost of imaging spectroscopy instrumentation.
Data sampling is a crucial yet often overlooked step in hyperspectral image analysis, which impacts the subsequent
results and their interpretation. In the selection of pixel spectra for the calibration of classification models, the spatial
information in HSI data can be exploited. In this paper, a variety of sampling strategies for selection of pixel spectra are
presented, exemplified through five case studies. The strategies are compared in terms of the proportion of global
variability captured, practicality and predictive model performance. The use of variographic analysis as a guide to the
spatial segmentation prior to sampling leads to the selection of representative subsets while reducing the variation in model
performance parameters over repeated random selection.