This is a quick update to some code posted while back, related to plotting filled polygons within a lattice panel function. After attempting to use the originally described function to plot data with NA, I quickly realized that a more robust approach was required-- panel.polygon() does not deal well with missing data. A new function of the same name is attached at the bottom of the page, and some code demonstrating its use is presented below. The rle() function (run-length encoding) does most of the difficult work of identifying contiguous chunks of non-missing data. Each chunk is plotted as a separate polygon, resulting in a (mostly) generalized panel function for plotting filled polygons within the lattice framework. Comments welcome.
FIgure: panel.tsplot() example
Demo
# Code originally by D.E. Beaudette and V. Mehtalibrary(lattice)library(RColorBrewer)# see attached file at bottom of pagesource('panel.tsplot.R')# setup query parametersrow <- 8 ; col <- 121 ; scale <- 1# build URL: this is the new approach to loading datau <- url(sprintf("http://www.climatechange.ca.gov/visualization/sei_temp/weadapt_www_site/data_export.php?format=csv&row=%i&col=%i&scale=%i&query_type=climatets", row, col, scale))# read file from URLx <- read.csv(u)# fix the datex$date <- as.Date(x$date)#### lets make things interesting and remove a couple slices of data##x$mean_temp[x$date > as.Date('2020-01-01') & x$date < as.Date('2025-01-01')] <- NAx$mean_temp[x$date > as.Date('2075-01-01') & x$date < as.Date('2090-01-01')] <- NA# get date ranged.range <- range(x$date)d.list <- seq(d.range[1], d.range[2], by='5 years')# setup colors and line typesarea.cols <- brewer.pal('Set1', n=9)line.cols <- rep(area.cols[1:2], each=3)line.lty <- rep(c(1,2,3), times=2)# customize plotting devicetrellis.par.set('superpose.polygon'=list(col=area.cols))trellis.par.set('superpose.line'=list(col=line.cols, lty=line.lty))trellis.par.set('layout.widths'=list(ylab.axis.padding=3))# plotxyplot(mean_temp ~ date, groups=emission, data=x, scales=list(y=list(alternating=3), x=list(format="%Y", cex=1, at=d.list)), auto.key=list(columns=2, rectangles=TRUE, lines=FALSE, points=FALSE, cex=0.75), xlab='Date', ylab="Avg Annual Temperature", panel=panel.tsplot)
Attachment: panel.tsplot.R
