contourG {GRASS} | R Documentation |
contour.G provides a simple interface between grass data objects and the contour()
function.
contourG(x, layer=NULL, xlab="", ylab="", reverse=NULL, add=FALSE, ...)
x |
GRASS metadata from gmeta() |
layer |
GRASS-ordered raster layer passed on to contour() |
xlab |
a title for the x axis, passed to plot() |
ylab |
a title for the y axis, passed to plot() |
reverse |
see help(reverse) |
add |
FALSE for new plot, TRUE to overlay layer on prior plot |
... |
parameters passed through to contour() |
The function uses asp=1
from the plot.window()
function to
ensure that the scales chosen to be equal on both axes, that is 1cm represents
the same units on each.
none
The functions in this package are intended to work with the GRASS geographical information system. The examples for wrapper functions will will work whether or not R is running in GRASS, and whether or not the current location is that of the data set used for the examples. Examples of interface functions will however (from version 0.2-2) only work outside GRASS, to avoid possible overwriting of GRASS database locations and/or files.
Roger S. Bivand, e-mail: Roger.Bivand@nhh.no.
http://grass.itc.it/statsgrass/index.html, Bivand, R. S., (2000) Using the R statistical data analysis language on GRASS 5.0 GIS data base files. Computers and Geosciences, 26, pp. 1043-1052.
plot.window
, contour
, plot.grassmeta
data(utm.maas) Zn.o <- as.ordered(cut(utm.maas$Zn, labels=c("insignificant", "low", "medium", "high", "crisis"), breaks=c(100, 200, 400, 700, 1000, 2000), include.lowest=TRUE)) G <- maas.metadata contourG(G) points(utm.maas$east, utm.maas$north, pch=unclass(Zn.o)) legend(x=c(269800, 270500), y=c(5652300, 5653000), pch=c(1:5), legend=levels(Zn.o)) title("Note equal east and north scales") contourG(G, kde2d.G(utm.maas$east, utm.maas$north, h=c(300,300), G=G, Z=utm.maas$Zn)*maasmask) points(utm.maas$east, utm.maas$north, pch=unclass(Zn.o)) legend(x=c(269800, 270500), y=c(5652300, 5653000), pch=c(1:5), legend=levels(Zn.o)) title("Kernel density representation of soil Zn")