trec: An R package for trend estimation and classification to support integrated assessment of the marine ecosystem and environmental factors

Solvang and Planque (2020) provided a trend estimation and classification (TREC) approach to estimating dominant common trends among multivariate time series observations. This approach was developed to improve communication among stakeholders like marine managers, industry representatives, non-governmental organizations, and governmental agencies as they investigate the common tendencies between a biological community in a marine ecosystem and the local environmental factors. The entire calculation procedure was originally implemented using MATLAB (ver.R2018b). In this paper, we present R package trec, which was motivated by the requests of readers of the Journal of Marine Science, published by the International Council for the Exploration of the Sea. The tasks of trend estimation and classification in the original program have been revised, and new features include an automatic icon assignment algorithm using a multinomial logistic discriminator. Implementation of this package involves three partitions corresponding to TREC1) estimating trends from observed time series data; TREC2) classifying two/three rough patterns; and TREC3) generating a table summarizing categories of common configurations and the automatic icon assignments to them.