[R] Reshape package: Casting data to form a grid

ONKELINX, Thierry Thierry.ONKELINX at inbo.be
Tue Aug 18 14:03:34 CEST 2009

Dear Steve,

You need something like this.

cast(Latitude ~ Longitude, data = finalframe, value = "Blaney", fun =



ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature
and Forest
Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,
methodology and quality assurance
Gaverstraat 4
9500 Geraardsbergen
tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be

To call in the statistician after the experiment is done may be no more
than asking him to perform a post-mortem examination: he may be able to
say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of
~ John Tukey

-----Oorspronkelijk bericht-----
Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
Namens Steve Murray
Verzonden: maandag 17 augustus 2009 18:53
Aan: r-help at r-project.org
Onderwerp: [R] Reshape package: Casting data to form a grid

Dear R Users,

I'm trying to use the 'cast' function in the 'reshape' package to
convert column-format data to gridded-format data. A sample of my
dataset is as follows:

  Latitude Longitude Temperature OrigLat  p-value Blaney
1      -90    -38.75          NA  -87.75 17.10167     NA
2      -90    135.75          NA  -87.75 17.10167     NA
3      -90     80.25          NA  -87.75 17.10167     NA
4      -90     95.75          NA  -87.75 17.10167     NA
5      -90     66.75          NA  -87.75 17.10167     NA
6      -90     75.75          NA  -87.75 17.10167     NA

I'm attempting to form a grid based on the OrigLat, Longitude and Blaney
columns, to form the rows, columns and values of the new grid

The command I've been using is:

cast_test <- cast(finalframe, finalframe$OrigLat~variable,
finalframe$Longitude~variable, finalframe$Blaney~variable)
Error: Casting formula contains variables not found in molten data:
finalframe$OrigLat, variable

And I've tried removing the ~variable suffixes:

cast_test <- cast(finalframe, finalframe$OrigLat, finalframe$Longitude,
Error: Casting formula contains variables not found in molten data:
-87.75-87.75 [etc etc]

I'm not sure how to get round this error, nor what the 'molten data' is
that the error is referring to. I'm assuming it means the data frame
presented above, yet the variables are clearly present!

Any help or advice on this would be most welcomed.

Many thanks,



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