[R] Fwd: only plot borders of a region in a scatter plot

[Duncan Murdoch]

On 04/08/2016 11:46 AM, Zun Yin wrote:
> Dear William, Duncan and Bert,
>
> Thanks a lot for your help and tips :D In fact the contour() plot still
> cannot solve my problem perfectly. As the resolution of my plot is very
> coarse, I want to a contour perfectly surround all grid cells in the river
> basin. In another word, I want all angle of the contour to be 90 degree.
> Another problem for the contour() is that the contour line doesn't close at
> where the value of neighbouring grid cell is NA. See the right side of the
> two contour lines (attachment). Do you know how I can get what I want?
> Thanks a lot :P

The second problem is easy:  just change your NA values to some new ID 
value, or change the test from

basiinID == ID

to

!is.na(basiinID) & basiinID == ID

The first one looks harder.

Duncan Murdoch

>
> Cheers,
>
>
> Zun Yin
>
> On Thu, Aug 4, 2016 at 5:09 PM, Bert Gunter <bgunter.4567 at gmail.com> wrote:
>
>> ... note the typo. It's:
>>
>> contour( basiinID == ID, level=0.5)
>>
>> :-)
>>
>>
>> -- Bert
>>
>>
>>
>> Bert Gunter
>>
>> "The trouble with having an open mind is that people keep coming along
>> and sticking things into it."
>> -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )
>>
>>
>> On Thu, Aug 4, 2016 at 8:03 AM, William Dunlap via R-help
>> <r-help at r-project.org> wrote:
>>> If 'basinID' is the matrix of basin identifiers you could draw an outline
>>> of the basin with identifier 'ID' with
>>>    coutour( basiinID == ID, level=0.5)
>>> Add 'add=TRUE' if you are overlaying this on an existing plot.
>>>
>>> Bill Dunlap
>>> TIBCO Software
>>> wdunlap tibco.com
>>>
>>> On Thu, Aug 4, 2016 at 1:51 AM, Zun Yin <yinzun2000 at gmail.com> wrote:
>>>
>>>> D
>>>> ear all,
>>>>
>>>> I have a matrix with ID of river basins (integer numbers). Now I want to
>>>> highlight one river basin in a map by plotting only the border. Like the
>>>> attached figure. Two river basins are highlighted by polygons. It is
>>>> created by ferret, but I prefer to implement it by R. Anybody know how
>> to
>>>> do it? Thanks a lot.
>>>>
>>>> Cheers,
>>>>
>>>> Zun Yin
>>>>
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>>
>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> 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.