[R] Excluding coordinates that fall within a circle

[Jeff Newmiller]

This is mostly a domain-specific question about coordinate conversion and algebra, not really about R. However, there are packages that could be useful for this problem that are discussed in the CRAN "Analysis of Spatial Data" Task View [1] and on the R-sig-geo mailing list [2].

Some points to get you started:

1) You need to know about georeferencing coordinate systems. In particular, what LatLon system are the coordinates you have measured in. The range of values in your data will be something to mention when you ask your question on R-sig-geo if they are to help you figure that out. 

2) A small sample of your data extracted from R with the dput function will be helpful. 

3) Read the Posting Guide. Note in particular that you need to tell your email client to use plain text format if you want to insure that the recipients see what you sent instead of some garbled version of it. 

[1] https://cran.r-project.org/view=Spatial
[2] https://stat.ethz.ch/mailman/listinfo/r-sig-geo
-- 
Sent from my phone. Please excuse my brevity.

On June 17, 2016 10:26:32 AM PDT, Alice Domalik <adomalik at sfu.ca> wrote:
>Hi List, 
>
>I'm working with some bird tracking data, and to filter the data set, I
>need to exclude points taken at the colony. 
>I would like to exclude coordinates from within a 500 meter radius of a
>point centered on the colony. 
>However, as an R novice, I'm not sure how to accomplish this. 
>
>My df looks like this: 
>
>AnimalID Latitude Longitude Datetime 
>
>Any suggestions would be greatly appreciated. 
>
>
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>
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