Introducing the R 'gimms' package
The R gimms package provides a set of functions to
- retrieve information about AVHRR GIMMS NDVI3g files currently available online;
- download (and re-arrange, in the case of older product versions) the half-monthly datasets;
- import downloaded files from native binary (ENVI) or NetCDF (.nc4) format directly into R based on the popular raster package;
- perform comprehensive quality control based on the companion quality flags;
- calculate monthly value composites (e.g., using the maximum value) from the half-monthly input data;
- and derive long-term monotonic trends from the Mann-Kendall test, optionally featuring pre-whitening to account for lag-1 autocorrelation.
This comprehensive tutorial introduces the package and includes a selection of application examples. For latest functionality updates and bug-fixes, please refer to the official gimms GitHub repository maintained by the Environmental Informatics working group at Philipps-Universität Marburg, Germany.