Change frequency heatmaps for temporal multivariate phenological data analysis

The huge amount of multivariate temporal data that has been produced in several applications demands the creation of appropriate tools for the analysis and pattern characterization of change. This paper introduces a novel image-based representation, named Change Frequency Heatmap (CFH), to encode temporal changes of multivariate numerical data. The method computes histograms of change patterns observed at successive timestamps. We validate the use of CFHs through the creation of a temporal change characterization tool to support complex plant phenology analysis, concerning the characterization of plant life cycle changes of multiple individuals and species over time. We demonstrate the potential of CFH to support visual identification of complex temporal change patterns, especially to decipher interindividual variations in plant phenology.