(This article was first published on

**NumberTheory » R stuff**, and kindly contributed to R-bloggers)To apply a data transformation on an axis in a ggplot, you can use coordinate transformations. For more detail see the ggplot2 documentation. A number of coordinate transformations is available, including `log10`

and `sqrt`

. However, if you want to perform a custom transformation this is not trivial. Say the transformation involves `x = 1/x`

. To get this transformation available you can define the following function (see `?trans_new`

for more details):

require(scales) # trans_new() is in the scales library one_over_trans = function() trans_new("one_over", function(x) 1/x, function(x) 1/x)

from now one you can use `one_over`

as a coordinate transform. Note that the name convention is `nameoftrans_trans`

. Example code:

qplot(carat, price, data=diamonds) + coord_trans(x = "log10", y = "one_over")

To

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