Hey, I know that volcano! It's walking distance from the Intermediate
school I attended.
To you it's a plot; to me it's a place.
So I offer you four scenarios.
1. You think of it as a place you know and have been.
In that case the "right" orientation is the one that best matches
what you are used to seeing.
For me, that would put the peak on the right of the plot.
2. You think of it as a patch in a map.
In that case the "right:" orientation is the one that matches the map.
That would put the peak at the bottom of the plot.
3. You think of it as a product of geological processes, and are
perhaps interested in
whether there is any connection between the orientation of the
volcano and the
direction the Auckland hot-spot (currently at White Island) was moving.
In that case you'd choose south-west -> north-east as the primary axis.
(I think. Not really sure.)
4. You think of it as a picture, an illustration in a textbook. It
might need to be cropped
vertically so you can fit another illustration on the same page.
For that and
perceptual reasons you want the major linear axis of the image to
be horizontal.
In that case, what we have now is a perfectly reasonable choice.
"Quality is fitness for use."
On Sun, 10 May 2020 at 12:44, Michael Sumner <mdsum...@gmail.com> wrote:
>
> Does anyone know why 'volcano' is oriented as it is?
>
> image(volcano) ## filled.contour is the same
>
> I know it's all arbitrary, but north-up is a pretty solid convention. Is
> there any reason why the classic 'image()' example data set would not
> default to this orientation?
>
> A Google map of the site (in Web Mercator):
>
> https://www.google.com/maps/place/Maungawhau+%2F+Mount+Eden/@-36.8763271,174.7619561,856m/data=!3m1!1e3!4m8!1m2!2m1!1smaungawhau!3m4!1s0x6d0d47db8d7bd1ff:0x8bcffe2a5c7360d2!8m2!3d-36.8666667!4d174.7666667
>
>
> For image(), the north-up orientation is 't(volcano[,ncol(volcano):1])'.
>
> If you are interested in a roughly georeferenced version I have code here:
>
> https://gist.github.com/mdsumner/20fe3ffa04421bf8e0517c19085e5fd8
>
> (Also see fortunes::fortune("conventions") )
>
> Best, Mike
>
>
> --
> Michael Sumner
> Software and Database Engineer
> Australian Antarctic Division
> Hobart, Australia
> e-mail: mdsum...@gmail.com
>
> [[alternative HTML version deleted]]
>
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