On 6/17/2008 6:59 AM, Steve Murray wrote:
Dear all,
I have used 'read.table' to create a data frame of 720 columns and 360 rows
(and assigned this to 'Jan'). The row and column names are numeric:
columnnames <- sprintf("%.2f", seq(from = -179.75, to = 179.75, length = 720)).
rnames <- sprintf("%.2f", seq(from = -89.75, to = 89.75, length = 360))
colnames(Jan) <- columnnames
rownames(Jan) <- rnames
A sample of the data looks like this:
head(Jan)
-179.75 -179.25 -178.75 -178.25 -177.75 -177.25 -176.75 -176.25 -175.75
-89.75 -56.9 -64.2 56.2 -90.0 56.9 -29.0 -91.0 34.0 -9.1
-89.25 37.9 19.3 -0.4 -12.3 -11.8 -92.1 9.2 -23.5 -0.2
-88.75 47.4 3.1 -47.4 46.4 34.2 6.1 -41.3 44.7 -10.3
-88.25 -20.3 34.5 -67.3 -99.9 37.9 -9.3 17.7 -17.2 63.4
-87.75 -46.4 47.4 12.4 -48.3 9.3 -33.8 38.1 10.8 -34.1
-87.25 -48.4 10.3 -89.3 -33.0 -1.1 -33.1 81.2 -8.3 -47.2
I'm hoping to get the whole dataset into the form of columns, so that, for
example, the first row (as shown above) would look like this:
Latitude Longitude Value
-89.75 -179.75 -56.9
-89.75 -179.25 -64.2
-89.75 -178.75 56.2
-89.75 -178.25 -90.0
-89.75 -177.75 56.9
-89.75 -177.25 -29.0
-89.75 -176.75 -91.0
-89.75 -176.25 34.0
-89.75 -175.75 -9.1
As you can see, this would require the repeated printing of the the row and
column names (in this case '-89.75') - so it's not just a case of rearranging
the data, but creating 'more' data too.
I've tried to achieve this using 'reshape' and 'stack' (their help files and
after looking through the mailing archives), but I'm obviously doing something
wrong. For reshape, I'm getting errors relating to the commands I enter, and
for stack, I can only produce two columns from my data (with the additional 3rd
column being a row count). In any case, these two columns refer to the wrong
values (it's producing output in the form of: row count number, Longitude,
Value).
I'd be very grateful if anyone could help me out with the commands I need to
enter in order to achieve the results I'm hoping for.
Here is an approach with reshape() on a much smaller example:
columnnames <- sprintf("%.2f", seq(from = -179.75, to = 179.75, length = 5))
rnames <- sprintf("%.2f", seq(from = - 89.75, to = 89.75, length = 3))
Jan <- as.data.frame(matrix(runif(3*5), ncol=5))
colnames(Jan) <- columnnames
rownames(Jan) <- rnames
Jan$Latitude <- rownames(Jan)
Jan.long <- reshape(Jan, idvar="Latitude", direction="long",
varying = list(columnnames),
v.names="Value",
timevar="Longitude",
times=columnnames)
Jan.long[] <- sapply(Jan.long, as.numeric)
Jan
-179.75 -89.88 0.00 89.88 179.75 Latitude
-89.75 0.9264005 0.5442698 0.3894998 0.8961858 0.1340782 -89.75
0.00 0.4719097 0.1961747 0.3108708 0.1663938 0.1316141 0.00
89.75 0.1426153 0.8985805 0.1600287 0.9004246 0.1052875 89.75
Jan.long
Latitude Longitude Value
-89.75.-179.75 -89.75 -179.75 0.9264005
0.00.-179.75 0.00 -179.75 0.4719097
89.75.-179.75 89.75 -179.75 0.1426153
-89.75.-89.88 -89.75 -89.88 0.5442698
0.00.-89.88 0.00 -89.88 0.1961747
89.75.-89.88 89.75 -89.88 0.8985805
-89.75.0.00 -89.75 0.00 0.3894998
0.00.0.00 0.00 0.00 0.3108708
89.75.0.00 89.75 0.00 0.1600287
-89.75.89.88 -89.75 89.88 0.8961858
0.00.89.88 0.00 89.88 0.1663938
89.75.89.88 89.75 89.88 0.9004246
-89.75.179.75 -89.75 179.75 0.1340782
0.00.179.75 0.00 179.75 0.1316141
89.75.179.75 89.75 179.75 0.1052875
You also might use expand.grid() as follows:
Jan.long2 <- cbind(expand.grid(rnames, columnnames), unlist(Jan[,1:5]))
Jan.long2[] <- sapply(Jan.long2, function(x){as.numeric(as.character(x))})
names(Jan.long2) <- c("Latitude", "Longitude", "Value")
Jan.long2
Latitude Longitude Value
-179.751 -89.75 -179.75 0.9264005
-179.752 0.00 -179.75 0.4719097
-179.753 89.75 -179.75 0.1426153
-89.881 -89.75 -89.88 0.5442698
-89.882 0.00 -89.88 0.1961747
-89.883 89.75 -89.88 0.8985805
0.001 -89.75 0.00 0.3894998
0.002 0.00 0.00 0.3108708
0.003 89.75 0.00 0.1600287
89.881 -89.75 89.88 0.8961858
89.882 0.00 89.88 0.1663938
89.883 89.75 89.88 0.9004246
179.751 -89.75 179.75 0.1340782
179.752 0.00 179.75 0.1316141
179.753 89.75 179.75 0.1052875
Many thanks,
Steve
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--
Chuck Cleland, Ph.D.
NDRI, Inc. (www.ndri.org)
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______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
