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]") 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
