On Thu, 14 Oct 2004, Petr Pikal wrote: > > > On 14 Oct 2004 at 10:00, Duncan Murdoch wrote: > > > On Thu, 14 Oct 2004 15:16:30 +0200, "Wolf, Michael" > > <[EMAIL PROTECTED]> wrote : > > > > >Dear list, > > > > > >are there any possibilities to fill a polygon with a point pattern or > > >with a symbol pattern like '+' oder '-' instead of shading lines? > > > > I don't think the graphics devices know how to do that, but you could > > program it yourself: > > > > Supposed interior(x,y) is a function that determines whether the > > points (x,y) are in the polygon, then just create a grid of locations, > > subset when interior(x,y) is true, and plot using pch='+'. > > > > I made a quick search and was unable to find a general implementation > > of the "interior" function for an arbitrary polygon; I'm a bit > > surprised about that. Hopefully someone else can point to one, > > Hi > > I think that you can find such functionity in splancs package > probably function pip() find if points are inside or outside of the > polygon. > > Cheers > Petr >
Going a bit further, you could use areapl() and gridpts() in splancs to return plotting points for the symbols that would give an even symbol per unit area coverage. This is a very similar question to: https://stat.ethz.ch/pipermail/r-help/2004-September/056351.html which was about dot density maps. A function to do that will be in the next maptools, but I think this is a bit different and is more like a hatching but with arbitrary symbols and chosen spacing - it can be done, but do you need this kind of symbology? Roger > > > > otherwise please write one, and document it and contribute it to R. > > It's a relatively standard algorithm, and would be useful. > > > > Duncan Murdoch > > > > ______________________________________________ > > [EMAIL PROTECTED] mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide! > > http://www.R-project.org/posting-guide.html > > Petr Pikal > [EMAIL PROTECTED] > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > -- Roger Bivand Economic Geography Section, Department of Economics, Norwegian School of Economics and Business Administration, Breiviksveien 40, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93 e-mail: [EMAIL PROTECTED] ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
