Dear R Users,

I am using the reshape package to reformat gridded data into column format 
using the code shown below. However, when I display the resulting object, a 
single column is fomed (instead of three) and all the latitude values (which 
should be in either column one or two) are collected at the bottom. Also, the 
NA values aren't removed, despite this being requested in the code.

Code:


# NetCDF file has been read in and is being processed...

arunoff_1986_temp <- get.var.ncdf(netcdf_1036_temp, "arunoff")


# Assign row and column names

columnnames <- sprintf("%.2f", seq(from = -89.75, to = 89.75, length = 360))
rnames <- sprintf("%.2f", seq(from = -179.75, to = 179.75, length = 720))

colnames(arunoff_1986_temp) <- columnnames
rownames(arunoff_1986_temp) <- rnames


# Melt into columnar format

arunoff_1986$Longitude <- rownames(arunoff_1986)
    # Note: If I do: arunoff_1986$Latitude <- rownames(arunoff_1986)  (i.e. 
change it to 'Latitude', I get the following: Warning message: In 
arunoff_1986$Latitude <- rownames(arunoff_1986) : Coercing LHS to a list ), 
thus proceed using 'Longitude' where no warning is apparent.


arunoff_long_1986 <- melt(arunoff_1986, id.var="Longitude", na.rm=TRUE)


> dim(arunoff_long_1986)
[1] 259560      2

>head(arunoff_long_1986, n=10)  # This displays what looks like one single 
>column, but is in fact two: column entitled "L1" is empty until the end of the 
>file, as shown by the 'tail' command below.
   value L1
1      
2      
3      
4      
5      
6      
7      
8      
9      
10     

> tail(arunoff_long_1986, n=10)
             value       L1
Latitude.351 85.25 Latitude
Latitude.352 85.75 Latitude
Latitude.353 86.25 Latitude
Latitude.354 86.75 Latitude
Latitude.355 87.25 Latitude
Latitude.356 87.75 Latitude
Latitude.357 88.25 Latitude
Latitude.358 88.75 Latitude
Latitude.359 89.25 Latitude
Latitude.360 89.75 Latitude



I'd be very grateful indeed if anyone is able to offer assistance by way of 
pointing out what I've done wrong. I've spent a long time working on this and 
trying various options, but am srill none the wiser! I'm aiming for three 
columns: Latitude, Longitude, 'value'. 

Many thanks for any help offered,

Steve

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