R help - Nov 2010 - Problems using Internal filledcontour: "dimension mismatch"

In order to gain a bit more control over the fill contour functionality I'm 
trying to use the Internal filledcontour function.   I wasn't able any 
documentation on this function and only one reference to it.   


I believe the code shown below is close because all the dimensions seem to be 
correct, but I'm still getting a "dimension mismatch" error and
the filled
contour doesn't occur.  Here is a listing of the actual
dimensions:
> length(ak.fan$y)
[1] 40
> dim(ak.fan$y)
NULL
> length(ak.fan$y)
[1] 40
> length(ak.fan$x)
[1] 40
> dim(ak.fan$z)
[1] 40 40
> length(lev.sd.vol)
[1] 5
> length(color_vals_green_to_yellow_to_red)
[1] 20

Note that I did try to use terrain.colors, but that also seemed to produce the 
same error.  I also replaced all the NA values hoping that would help work 
around this error.   I'm kind of coming to the end of my guesses about how
to
work around this error, so any feedback and advice is greatly appreciated.  



library(akima)

hyp_distance<-seq(1,15)
angle_deg_val<-seq(0,15)


x_distance_val<-NULL
y_distance_val<-NULL

for(ii in 1:length(hyp_distance))
{
        for(jj in 1:length(angle_deg_val))
        {
               
x_distance_tmp<-hyp_distance[ii]*cos(angle_deg_val[jj]*pi/180)
               
y_distance_tmp<-hyp_distance[ii]*sin(angle_deg_val[jj]*pi/180)
                
                x_distance_val<-c(x_distance_val, x_distance_tmp)
                y_distance_val<-c(y_distance_val, y_distance_tmp)
        }
        
}


temperature_vals<-rnorm(length(x_distance_val), 75, 2)

temp_samples<-cbind(x_distance_val, y_distance_val, temperature_vals)

temp_samples_DF<-data.frame(x = x_distance_val, y =  y_distance_val, z = 
temperature_vals)


ak.fan <- interp(temp_samples[,1], temp_samples[,2], temp_samples[,3] )

ak.fan.original<-ak.fan

# Get rid of all the NA values and replace with zero values...
ak.fan$z[which(is.na(ak.fan$z))]<-0.0

length_val<-floor(max(temperature_vals) - min(temperature_vals))*2

color_vals_red_to_yellow_to_green<-colorRampPalette(c("red",
"yellow", "green"),
space="Lab")(length_val)
color_vals_green_to_yellow_to_red<-colorRampPalette(c("green",
"yellow", "red"),
space="Lab")(length_val)

plot(1,1, col = 0, xlim = c(min(x_distance_val), max(x_distance_val)), ylim = 
c(min(y_distance_val), max(y_distance_val)), xlab = "Room X Position
(FT)", ylab
= "Room Y Position (FT)", main = "Room Temp vs Position")

grid()


# filled.contour(ak.fan, col = color_vals_red_to_yellow_to_green)
# filled.contour(ak.fan, col = color_vals_green_to_yellow_to_red)

lev.sd.vol <- pretty(range(na.omit(unique(as.numeric(ak.fan$z)))), 4)

.Internal(filledcontour(as.double(ak.fan$y), as.double(ak.fan$x), 
as.double(ak.fan$z), as.double(lev.sd.vol), col = 
color_vals_green_to_yellow_to_red))