[R] point.in.polygon help

[MacQueen, Don]

First suggestion is to ask the question on r-sig-geo.

There is the  over()
function in the sp package, though it may require you to put your points
in a spatial class object.


For a crude brute-force approach that does not easily generalize, but
might be the quickest short-term solution for you right now, and assuming
your object has just a single polygon, try this:

  your.spdf at polygons[[1]]@Polygons[[1]]@coords


That should give you a two column matrix representing your polygon.

You may need to remove the last row for pol.x and pol.y, since in this
implementation the last row = the first row.


-Don

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 5/21/13 1:29 PM, "karengrace84" <kgfisher at alumni.unc.edu> wrote:

>I am new to mapping with R, and I would like to use the point.in.polygon
>function from the sp package, but I am unsure of how to get my data in the
>correct format for the function. The generic form of the function is as
>follows:
>
>point.in.polygon(point.x, point.y, pol.x, pol.y, mode.checked=FALSE)
>
>I have no problem with the point.x and point.y inputs. I have a list of
>gps
>longitudes and latitudes that will go in fine. My problem is with the
>pol.x
>and pol.y input. My polygon is currently in the form of a
>SpatialPolygonsDataFrame created by inputting shp files with the rgdal
>package.
>
>How do I get a numerical array of the x- and y-coordinates from my polygon
>that will go into the point.in.polygon function?
>
>
>
>--
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>
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