[R-sig-Geo] spplot, polygons, and line density fill

[Hadley Wickham]

Hi Matthew,

The basic problem is that there is no low-level support for pattern
fills in grid. To resolve this, you need:

 * some way of parameterising pattern fills using other grobs.  A good
start would be to think about filling a region with regularly spaced
lines of different angles.

 * some way of clipping that filling pattern to arbitrary polygons
(not sure how hard that is to do)

 * some way of making it efficient, maybe using rasterGrob.

I haven't looked it into enough to know how hard or each each of these
steps would be.  You might try also asking on the ggplot2 mailing
list, because other's may have a better idea than me.

Hadley

On Mon, Apr 25, 2011 at 11:38 AM, Matthew Landis <landis at isciences.com> wrote:
> Hi Hadley,
>
> Can you elaborate on what you mean by "not...easy"?  Does that mean
> "impossible", or  "not currently possible without writing a lot of low level
> code",  or something else?  Are there any resources you know that might help
> to implement it?
>
> Thanks,
>
> Matt
>
> On 4/25/2011 12:07 PM, Hadley Wickham wrote:
>>
>> Unfortunately this type of fill is not currently easy with grid
>> graphics, which is what both spplot and ggplot2 use.
>>
>> Hadley
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~
> Matthew Landis, Ph.D.
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> ISciences, LLC
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>



-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/