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" )

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