[R] writing polygons/segments to shapefiles (.shp) or other ArCGIS compatible file

[Patrick Giraudoux]

Thanks a lot for the hints. I will try.  Actually I was focusing (in a first stage) on simple segments (small mammal traplines...).
I turned the problem out writing some lines to export the coordinates into a "simple" GRASS ascii file, imported it into GRASS as
vector file and then used the export tool to get  shapefiles...  Not that direct: needs to have GRASS installed and an elementary
knowledge on the export/import commands in this open source GIS.

It would be fantastic to have the reverse functions of Map2poly(Map), Map2lines(Map), Map2points(Map) read.shape (eg poly2map,
lines2map, points2map, and write.map) to write shapefiles.... I must however admit that I don't know enough about shapefile formats
and R programming to do this by myself... and I would unfortunately be really out of my current job in the university...


----- Original Message ----- 
From: "Stephane DRAY" <dray at biomserv.univ-lyon1.fr>
To: "Patrick Giraudoux" <patrick.giraudoux at univ-fcomte.fr>; "r-help" <r-help at stat.math.ethz.ch>
Sent: Wednesday, February 25, 2004 5:35 PM
Subject: Re: [R] writing polygons/segments to shapefiles (.shp) or other ArCGIS compatible file


> There is a little problem with the approach I described in my previous email.
> In ADE-4, coordinates are given in pixel and so Y are inverted. You must
> invert your Y coordinates to obtain the good representation in ArcView. An
> example:
>
>  > library(ade4)
>  > library(shapefiles)
>  > library(maptools)
>  > try1 <- read.shapefile(paste(ShapeDir, "columbus", sep="/"))
>  > shppolys <- shape2poly(try1, as.character(try1$dbf$dbf$NEIGNO))
>  > obj=poly2area(shppolys)
>  > obj[,3]=-obj[,3]
>  > write.table(obj,"try.area",col.names=F,quote=F,row.names=F)
>  >
>
> Then, use the 'From AREA' function in AVADE.
>
>
>
> At 10:32 25/02/2004, Patrick Giraudoux wrote:
> >I am not sure a previous e-mail reached the list (no mail aknowledgement
> >from R-boundle etc.). The question was how to write polygon
> >or segment coordinates into a shapefile set or any other ArcGIS supported
> >format. The library shapefiles seems to do something but
> >the documentation is a bit beyond of my mind.... and I cannot get the
> >meaning of the functions write**** and its application to the
> >case below:
> >
> >In simple words, is there a somewhere a function taking polygon
> >coordinates (or simple segments) within R to a "ready to read" set
> >of files ***.shp, ***.shx, etc...
> >
> >Thanks in advance for any hint
> >
> >Patrick
> >
> >
> >
> >----- Original Message -----
> >From: "Patrick Giraudoux" <patrick.giraudoux at univ-fcomte.fr>
> >To: "r-help" <r-help at stat.math.ethz.ch>
> >Sent: Wednesday, February 25, 2004 1:08 PM
> >Subject: writing polygons/segments to shapefiles (.shp)
> >
> >
> > > Dear all,
> > >
> > > The library maptools offers a fantastic support for shapefile reading.
> > >
> > > Is there a R library available permitting the writing of polygon or
> > segment coordinates into shapefile?
> > >
> > > Thanks for any hint,
> > >
> > > Patrick Giraudoux
> > >
> > >
> > >
> > >
> >
> >______________________________________________
> >R-help at stat.math.ethz.ch mailing list
> >https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> >PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>
> Stéphane DRAY
> -------------------------------------------------------------------------------------------------- 
>
> Département des Sciences Biologiques
> Université de Montréal, C.P. 6128, succursale centre-ville
> Montréal, Québec H3C 3J7, Canada
>
> Tel : 514 343 6111 poste 1233
> E-mail : stephane.dray at umontreal.ca
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