[R-sig-Geo] Changing axes of a plot

[Robert J. Hijmans]

Ogbos,

You can do this:

library(raster)
xy<-cbind(x, y)
r <- rasterize(xy, raster(nrow=120, ncol=60), fun=sum)

rb <- rev(rainbow(255,s=1,v=1,start=0,end=7/12,gamma=1,alpha=1))
image(r, col=rb, ylab = "Longitude", xlab="Latitude" )


Or, in your code, instead of this
z = t(grid3)

this might work:
z =  <- t(grid3[nrow(grid3):1,])

Robert

On Sun, Nov 21, 2010 at 10:51 PM, ogbos okike <ogbos.okike at gmail.com> wrote:
> Dear all,
> I tried to use the code below to generate 3 X 3 grid of latitude-longitude
> data. I use image to view the grid. However, latitude and longitude are on
> the wrong axes.  Thus, I want to swap the axes. I tried to swap x and y in:
> image(x, ..) that did not help. I also wish to add color code to the plot.
> Thanks for kind help.
>
>  portion of the data:
> -3.3851  -65.3236
>  -3.2696  -65.2364
>  -3.2679  -65.2349
> -17.6404  164.7025
>  -4.8285  148.8214
>  2.6477  -67.6568
>  -0.2350  -73.4833
> -16.8655   40.9587
>  8.1179  -61.6474
>  -0.2755   93.3401
> -17.1733  119.9011
>  1.1245  -69.7640
> -20.0035 -149.3088
>  -3.4200  177.8753
>  3.0133  -67.5590
>  15.4684  -21.9331
> -17.6166  120.2656
> -17.3888  165.9368
> -17.6953  164.7335
>  -1.8623  -74.0017
>  -3.3562  -71.1195
> -11.5775  130.1496
>
> code:
> xy<-matrix(c(x, y), ncol=2)
>
> # 3 deg grid for counts
> grid3 <- matrix(0, nrow=120, ncol=60)
>
> # accumulate counts of points in cells
> for (i in 1:nrow(xy)) {
>  if (xy[i, 1] == 180)
>  ix = nrow(grid3)
>  else
>  ix <- floor((xy[i,1] + 180) / 3) + 1
>
>  if (xy[i, 2] == 90)
>  iy = ncol(grid3)
>  else
>  iy <- floor((xy[i,2] + 90) / 3) + 1
>
>  # catch any subscript errors
>  tryCatch(
>  grid3[ix, iy] <- grid3[ix, iy] + 1,
>  error = function(e) cat("Ignoring point out of bounds:", xy[i,], "\n") )
> }
> rb<-rev(rainbow(255,s=1,v=1,start=0,end=7/12,gamma=1,alpha=1))
> image( x = seq(-88.5, 88.5, 3), y = seq(-178.5, 178.5, 3), z = t(grid3),
> col=rb, ylab = "Longitude", xlab="Latitude" )
>
>        [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at stat.math.ethz.ch
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>