Generating a polygon around points
Your question seems to need an answer to, "How do you find a convex hull
on a sphere?" Google has many references.
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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]]
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