Perfect, thanks very much. I couldn't see the xlim/ylim solution which is
really neat, and clearly better than my suggestion.

Cheers, Mike.


On Wed, Apr 17, 2013 at 6:15 PM, Prof Brian Ripley <ripley@stats.ox.ac.uk>wrote:

> On 12/04/2013 12:27, Michael Sumner wrote:
>
>> Hello, I would like to suggest the following change to image.default in
>> src\library\graphics\R\image.**R:
>>
>> 98c98
>> <       plot(NA, NA, xlim = xlim, ylim = ylim, type = "n", xaxs = xaxs,
>> ---
>>
>>>        plot(x[1], y[1], xlim = xlim, ylim = ylim, type = "n", xaxs =
>>> xaxs,
>>>
>>
>>
> I think xlim, ylim is a better idea: this relies on range() preserving the
> class.
>
> Done now (in R-devel pro tem).
>
>
>  This provides all the support of axis.POSIXt that plot.default gives,
>> currently the default new plot in image.default uses NAs and the axis
>> class
>> is ignored. This is nice for plotting time series data stored in a matrix.
>>
>> Here's a dummy example that shows usage with my change:
>>
>> data(volcano)
>> x <- list(x = Sys.time() + seq(1, 1e6, length = nrow(volcano)), y =
>> 1:ncol(volcano), z = volcano)
>>
>> ## date-time formatting on the x-axis
>> image(x)
>>
>> ## date-time formatting on the y-axis
>> image(x$y, x$x, t(x$z))
>>
>> Without the change we get the very large underlying numeric values for the
>> times on the axis.
>>
>> We can still override the default axis to do a workaround: :
>> image(x, axes = FALSE)
>> axis.POSIXct(x$x, side = 1)
>>
>> Cheers, Mike.
>>
>>
>>
>>
>
> --
> Brian D. Ripley,                  ripley@stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~**ripley/<http://www.stats.ox.ac.uk/~ripley/>
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595
>



-- 
Michael Sumner
Hobart, Australia
e-mail: mdsumner@gmail.com

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