No wonder I didn't understand your constraints... you didn't state them. In
fact, I think you still haven't stated them. Perhaps you need a map outline?
Or, you could just create a polygon manually? Isocline of a two-D kernel
density estimate or kriging fit? Manually partition your data into regions
which are convex? There might be precedents in the literature on your topic.
Appropriate selection of of algorithms is not really on topic here, though.
---------------------------------------------------------------------------
Jeff Newmiller The ..... ..... Go Live...
DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go...
Live: OO#.. Dead: OO#.. Playing
Research Engineer (Solar/Batteries O.O#. #.O#. with
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Sent from my phone. Please excuse my brevity.
On August 15, 2014 8:22:55 AM PDT, Bob O'Hara <rni....@gmail.com> wrote:
>Unfortunately my region isn't convex, and I don't want to end up
>predicting
>the distribution of a forest-dwelling bird in the Atlantic ocean...
>
>Bob
>
>
>On 15 August 2014 17:15, Jeff Newmiller <jdnew...@dcn.davis.ca.us>
>wrote:
>
>> Not really sure I understand your constraints, but perhaps
>>
>> RSiteSearch("convex hull ")
>>
>> might help?
>>
>---------------------------------------------------------------------------
>> Jeff Newmiller The ..... ..... Go
>Live...
>> DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live
>> Go...
>> Live: OO#.. Dead: OO#..
>Playing
>> Research Engineer (Solar/Batteries O.O#. #.O#. with
>> /Software/Embedded Controllers) .OO#. .OO#.
>rocks...1k
>>
>---------------------------------------------------------------------------
>> Sent from my phone. Please excuse my brevity.
>>
>> On August 15, 2014 7:51:37 AM PDT, Bob O'Hara <rni....@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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