Re: [R] Get contour of a map

From: Barry Rowlingson <>
Date: Tue, 24 May 2011 09:18:10 +0100

On Mon, May 23, 2011 at 8:00 PM, Duncan Murdoch <> wrote:
> On 11-05-23 5:55 AM, Pierre Bruyer wrote:

> I think writing that would be hard, but you can fake it.  Find the range of
> z first to work out the contour levels you want, then put very large values
> around the outside of the z matrix.  (You can't use Inf, but big finite
> values will work.)

 I had a play with this yesterday, expecting gPolygonize from rgeos to do the heavy lifting. But all I could make it do with contours from the standard volcano data, converted to the appropriate SpatialLines form, was segfault. Works fine on the examples given in the gPolygonize docs.

 That was an end-of-day ten minute experiment, so I might have another go later.

B mailing list PLEASE do read the posting guide and provide commented, minimal, self-contained, reproducible code. Received on Tue 24 May 2011 - 08:20:24 GMT

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