[R] Generating a polygon around points

David Winsemius dwinsemius at comcast.net
Fri Aug 15 17:55:40 CEST 2014

On Aug 15, 2014, at 8:15 AM, Jeff Newmiller wrote:

> Not really sure I understand your constraints, but perhaps
> RSiteSearch("convex hull ")

RSiteSearch has really been broken for some time now. (You get the headers but the links are all broken. A more effective way of searching the existing CRAN package base (but I think r-forge and github will be missed) is:

findFn("convex hull ")

I use Markmail to search the archives, but one can also use Gmane or Rseek.org. 

Both markmail and gmane have the defect that copied code comes to my console or editor without line-ends. If anyone has a hint on how to avoid that annoyance, I'll be in your debt.


> might help?
> ---------------------------------------------------------------------------
> Jeff Newmiller                        The     .....       .....  Go Live...
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> Sent from my phone. Please excuse my brevity.
> On August 15, 2014 7:51:37 AM PDT, Bob O'Hara <rni.boh at gmail.com> wrote:
>> I've been struggling for half a day on what should be a simple
>> problem...
>> I have a data frame of lat/long coordinates that describe a region, and
>> I
>> want to draw a polygon around them so I can use that as a boundary (to
>> be
>> thrown at INLA, but those details aren't important). The coordinates
>> are
>> almost on a regular grid: there is some variation in latitude (because
>> we're on a globe).
>> If the coordinates were on a regular grid, I could use as.owin() to
>> create
>> a mask, and go on from there (I have code that will work). But
>> as.owin()
>> doesn't like unevenly spaced points.
>> Can anyone suggest a way to sort this out? Preferable without having to
>> mess around transforming the coordinates.
>> Bob
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David Winsemius
Alameda, CA, USA

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