Is it possible to create a 3d contour plot without continuous data in R?

问题

I want to create a contour of variable z with the x,y,z data. However, it seems like we need to provide the data in increasing order.

I tried to use some code but it gave me the error.

I tried the following code: Trial 1:

age2100 <- read.table("temp.csv",header=TRUE,sep=",")

x <- age2100$x
y <- age2100$y
z <- age2100$z

contour(x,y,z,add=TRUE,col="black")

I got the following error

Error in contour.default(x, y, z, add = TRUE, col = "black") : increasing 'x' and 'y' values expected

I then tried to use ggplot2 to create the contour. I used the following code:

library("ggplot2")
library("MASS")
library("rgdal")
library("gpclib")
library("maptools")
age2100 <- read.table("temp.csv",header=TRUE,sep=",")
v <- ggplot(age2100, aes(age2100$x, age2100$y,z=age2100$z))+geom_contour()
v

I got the following error:

Warning message:

Not possible to generate contour data 

Please find the data on the following location https://www.dropbox.com/s/mg2bo4rcr6n3dks/temp.csv

Can anybody tell me how to create the contour data from the third variable (z) from the temp.csv ? I need to do these many times so I am trying to do on R instead of Arcgis.

回答1:

Here is an example of how one interpolates using interp from the akimapackage:

age2100 <- read.table("temp.csv",header=TRUE,sep=",")

x <- age2100$x
y <- age2100$y
z <- age2100$z

require(akima)

fld <- interp(x,y,z)

par(mar=c(5,5,1,1))
filled.contour(fld)

Here is an alternate plot using the imagefunction (this allows some flexibility to adding lower level plotting functions (requires the image.scale function, found here):

source("image.scale.R") # http://menugget.blogspot.de/2011/08/adding-scale-to-image-plot.html

x11(width=5, height=6)
layout(matrix(c(1,2), nrow=1, ncol=2), widths=c(4,1), height=6, respect=TRUE)
layout.show(2)

par(mar=c(4,4,1,1))
image(fld)
contour(fld, add=TRUE)
points(age2100$x,age2100$y, pch=".", cex=2)

par(mar=c(4,0,1,4))
image.scale(fld$z, xlab="", ylab="", xaxt="n", yaxt="n", horiz=FALSE)
box()
axis(4)
mtext("text", side=4, line=2.5)

来源：https://stackoverflow.com/questions/14375320/is-it-possible-to-create-a-3d-contour-plot-without-continuous-data-in-r