On Monday 17 August 2009, Markus Neteler wrote: > On Mon, Aug 17, 2009 at 9:33 AM, Roger Bivand<[email protected]> wrote: > > On Sun, 16 Aug 2009, Markus Neteler wrote: > >> Hi, > >> > >> I am plotting elevation against temperature and have the problem that > >> including all points leads to heavy slow graphs... Reducing the raster > >> resolution is not a solution since it does not maintain the > >> characteristics > >> of the graph (since GRASS is using nearest neighbor). > > > > One point initially. I'm assuming that you are using a Linux platform - > > on this platform, there is an order of magnitude speedup if you plot on > > screen without "cairo", the default x11 type= - try using type="Xlib", > > which is much faster but not so refined. > > (yes, Linux) > I have searched around bit I am not entirely sure to which function > this type parameter belongs. > > > Given that, consider the cex= argument for varying symbol size, and maybe > > the pch="." possibility for using a single pt. point. They still all get > > drawn, so there is no time saving, but they may be more visible. > > I am currently plotting like this: > plot(data$dem ~ data$raw) > points(data$dem ~ data$filt2, col="yellow", cex=0.5, pch=3) > points(data$dem ~ data$rst, col="green", xlab="LST value [°C]", > ylab="elevation [m]", pch=2) > abline(lm(data$dem ~ data$raw)) > abline(lm(data$dem ~ data$filt2), col="yellow") > abline(lm(data$dem ~ data$rst), col="green", xlab="LST value [°C]", > ylab="elevation [m]")
just a quick note on style: # simpler notation: plot(dem ~ raw, data=data, xlab="LST value [°C]", ylab="elevation [m]") points(dem ~ filt2, data=data, col="yellow", cex=0.5, pch=3) points(dem ~ rst, data=data, col="green", pch=2) also note that 'xlab' and other related commands need to be put into a high-level plotting command like 'plot()' finally, you might be able to make the plot in one command with some incantation of xyplot() from the lattice package. did you have a chance to try the kde2() function from MASS? Cheers, Dylan > So the backgound (largest) cloud comes in back circles, > the interim (smaller) in yellow crosses with many of them in the circles, > and the upper point could (smallest) in green triangles. > I guess the real problem are the 826896 * 3 points in the plot. > > > For very large data sets, consider hexbin() in the hexbin package - I'm > > not sure how best to display three data sets. For single scatterplots, it > > is very powerful. Maybe contours of 2D densities of the extra data sets > > could be overlaid over a base hexbin plot? There is an informative > > vignette in hexbin. > > Oh, this is interesting! Thanks, > Markus > _______________________________________________ > grass-stats mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-stats -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ grass-stats mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-stats
