Hi Bob, You probably want to have a look at the package alphahull.
Cheers, Tsjerk On Fri, Aug 15, 2014 at 5:25 PM, Clint Bowman <cl...@ecy.wa.gov> wrote: > Your question seems to need an answer to, "How do you find a convex hull > on a sphere?" Google has many references. > > Clint Bowman INTERNET: cl...@ecy.wa.gov > Air Quality Modeler INTERNET: cl...@math.utah.edu > Department of Ecology VOICE: (360) 407-6815 > PO Box 47600 FAX: (360) 407-7534 > Olympia, WA 98504-7600 > > USPS: PO Box 47600, Olympia, WA 98504-7600 > Parcels: 300 Desmond Drive, Lacey, WA 98503-1274 > > > On Fri, 15 Aug 2014, Bob O'Hara 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 >> >> -- >> Bob O'Hara >> >> Biodiversity and Climate Research Centre >> Senckenberganlage 25 >> D-60325 Frankfurt am Main, >> Germany >> >> Tel: +49 69 798 40226 >> Mobile: +49 1515 888 5440 >> WWW: http://www.bik-f.de/root/index.php?page_id=219 >> Blog: http://occamstypewriter.org/boboh/ >> Journal of Negative Results - EEB: www.jnr-eeb.org >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/ >> posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> >> > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/ > posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > -- Tsjerk A. Wassenaar, Ph.D. [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.