[R] the volcano orientation

[John]

Out of curiosity, and considering the bewildering array of projections
and grids in use for various mapping purposes, you seem to be saying in your
example 2 that the grid coordinates number south to north and east to
west.  Given scale of the coordinate numbers, would that be a national
grid system employed in New Zealnd?

J. W. Dougherty

On Mon, 11 May 2020 13:56:49 +1200
"Richard O'Keefe" <raoknz using gmail.com> wrote:

> 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 <mdsumner using 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: mdsumner using gmail.com
> >
> >         [[alternative HTML version deleted]]
> >
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