Patrick Giraudoux
2004-Feb-25 15:32 UTC
[R] writing polygons/segments to shapefiles (.shp) or other ArCGIS compatible file
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 > > > >
Stephane DRAY
2004-Feb-25 16:15 UTC
[R] writing polygons/segments to shapefiles (.shp) or other ArCGIS compatible file
I think It could not be done for the moment .. Perhaps, I am wrong ! In the package maptools, there is read.shape shape2poly, shape2line... These functions allow to read shapefiles files but not to write it. With the shapefiles package you can write shape object to files. I think that one solution is to write poly2shape, lines2shape,....or perhaps a more general write.Maps (to save Maps in GIS file format). Another and provisory solution exist. I have write an arcview 3.x extension (AVADE) to allow the interface between Arc-View and ADE-4 software. You can download the extension at www.steph280.freesurf.fr. If you have a poly object, you can convert it to an area object (poly2area in the ade4 library) save the area object within a file with write.table and convert this text file to a shapefile with the AVADE extension in Arcview. Hope this helps, 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.htmlSt?phane DRAY -------------------------------------------------------------------------------------------------- D?partement des Sciences Biologiques Universit? de Montr?al, C.P. 6128, succursale centre-ville Montr?al, Qu?bec H3C 3J7, Canada Tel : 514 343 6111 poste 1233 E-mail : stephane.dray at umontreal.ca -------------------------------------------------------------------------------------------------- Web http://www.steph280.freesurf.fr/
Stephane DRAY
2004-Feb-25 16:35 UTC
[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.htmlSt?phane DRAY -------------------------------------------------------------------------------------------------- D?partement des Sciences Biologiques Universit? de Montr?al, C.P. 6128, succursale centre-ville Montr?al, Qu?bec H3C 3J7, Canada Tel : 514 343 6111 poste 1233 E-mail : stephane.dray at umontreal.ca -------------------------------------------------------------------------------------------------- Web http://www.steph280.freesurf.fr/