A S4 class for the Interval level result of an Intensity analysis. Can be
plotted with the plot method
intervalData receives a table containing 4 columns
in the following format:
<fct>. The period of interest [Yt, Yt+1].
<dbl>. Changed area on the Interval level (%).
<dbl>. Annual intensity of change for a time
period [Yt, Yt+1].
<dbl>. Uniform intensity for a LUC category change in a time
period of interest.
tibble. A table with the results of an Intensity analysis at the Interval level (St and U values).