A question regarding cex and pch="." in lattice
On Feb 6, 2007, at 4:05 PM, Prof Brian Ripley wrote:
How do you know the points are not being plotted? All you can tell is that your graphics card / monitor / X11 driver is not displaying them, not at all the same thing.
Yes, that is what I meant but I suppose I conveyed it wrongly.
My guess is that the rectangle is being displayed only if the differences in its discretized x and y coordinates are both positive. R tries hard to ensure that pch='.', cex=1 does always display a point, but not for smaller cex.
This could be the case. Thanks Saptarshi
On Tue, 6 Feb 2007, Saptarshi Guha wrote:
Hello, I'm using lattice and opened an X11 device with the following call X11(width=5,height=5,pointsize=1) I then ran the following code library(lattice) x<-rnorm(30,sd=2) y<-runif(30) xyplot(y~x,pch=".",col="black",cex=1) If i remove "cex=1", not all the points are plotted. From ?X11, i read,"pch='.' with cex=1 corresponds to a rectangle of sides the larger of one pixel and 0.01 inch" By way of information, i'm using a Dell 30", where the the pixel pitch is 0.250mm(0.0098 inch). My question, why is that some of the points are not being plotted when remove cex=1 ?
The default cex for this plot is 0.8. See trellis.par.get
("plot.symbol").
Regards Saptarshi Saptarshi Guha | sapsi at pobox.com | http://www.stat.purdue.edu/~sguha [[alternative HTML version deleted]]
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