Adding labels within lattice panels by group

The other day I had data that showed the development of many products over time. I grouped the products into categories and visualised the data as line graphs in lattice. But instead of adding an extensive legend to the plot I wanted to add labels to each line’s latest point. How do you do that? It turns out that panel.groups is there to help again. Here is my solution: R code

Using planel.groups in lattice

Last Tuesday I attended the LondonR user group meeting, where Rich and Andy from Mango argued about the better package for multivariate graphics with R: lattice vs. ggplot2. As part of their talk they had a little competition in visualising London Underground performance data, see their slides. Both made heavy use of the respective panelling / faceting capabilities. Additionally Rich used the panel.groups argument of xyplot to fine control the content of each panel.