A data frame has one factor, one date, and one numeric column. When I plot these using the default pch of the open circle (first attachment), xyplot(TDS ~ sampdate | she.s, data = sheep.cast, main = 'TDS in Sheep Creek', ylab = 'Concentration (mg/L)', xlab = 'Time') I see the higher concentration points toward the right on several panels. But, when I change to using a line type (second attachment), xyplot(TDS ~ sampdate | she.s, data = sheep.cast, type = 'l', main = 'TDS in Sheep Creek', ylab = 'Concentration (mg/L)', xlab = 'Time') the higher concentrations are connected to points far to the left (earlier years). I expected to see a line with a few spikes toward the right sides of the panels. Where do I start to look for the reason for this behavior? TIA, Rich -------------- next part -------------- A non-text attachment was scrubbed... Name: sheep-TDS-year-dot.pdf Type: application/pdf Size: 6593 bytes Desc: URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20120101/1ff6eec5/attachment.pdf> -------------- next part -------------- A non-text attachment was scrubbed... Name: sheep-TDS-year-line.pdf Type: application/pdf Size: 6317 bytes Desc: URL: <https://stat.ethz.ch/pipermail/r-help/attachments/20120101/1ff6eec5/attachment-0001.pdf>
Lattice: Understanding How Points Connected by Lines
3 messages · Rich Shepard, David Winsemius
On Sun, 1 Jan 2012, Rich Shepard wrote:
Where do I start to look for the reason for this behavior?
Perhaps the dates are not in sequence? So I need to use zoo to order the dates sequentially? Rich
On Jan 1, 2012, at 5:50 PM, Rich Shepard wrote:
A data frame has one factor, one date, and one numeric column. When I plot these using the default pch of the open circle (first attachment), xyplot(TDS ~ sampdate | she.s, data = sheep.cast, main = 'TDS in Sheep Creek', ylab = 'Concentration (mg/L)', xlab = 'Time') I see the higher concentration points toward the right on several panels. But, when I change to using a line type (second attachment), xyplot(TDS ~ sampdate | she.s, data = sheep.cast, type = 'l', main = 'TDS in Sheep Creek', ylab = 'Concentration (mg/L)', xlab = 'Time') the higher concentrations are connected to points far to the left (earlier years). I expected to see a line with a few spikes toward the right sides of the panels. Where do I start to look for the reason for this behavior?
You should look at the structure of your dataset variables and the order in which they occur ... none of which is "visible" in what you have offered.
David Winsemius, MD West Hartford, CT