[R-sig-Geo] Plotting simple features sf with ggplot2

[Manuel Spínola]

Thank you very much Michael.

It works.

Manuel

2016-12-07 16:43 GMT-06:00 Michael Sumner <mdsumner at gmail.com>:

> On Thu, Dec 8, 2016, 04:21 Edzer Pebesma <edzer.pebesma at uni-muenster.de>
> wrote:
>
>
>
> On 07/12/16 17:49, Manuel Spínola wrote:
> > Dear list members,
> >
> > Is there a way to plot a simple features (sf) multipolygon (imported
> > shapefile) using ggplot2?
>
> Short answer is: not yet, I'm waiting for some help on this.
>
> There has been quite some discussion about this issue here:
>
> https://github.com/edzer/sfr/issues/88
> >
> > Similar to plotting a SpatialPolygonDataFrame  with ggplot2 using the
> > function fortify first to convert the SPDF to a data frame.
> >
>
> I think there is now a majority opinion that fortify is not such a good
> idea for simple feature (or in general: spatial) geometries.
>
>
> It's not a great idea, but you can do it and it already works.
>
> - it treats a layer as a set of grouped coordinates, rather than as
> separate objects
>
> - it wastes memory, by copying identifying attributes from the nested list
> hierarchy to each coordinate
>
> - it can't work with mixed topology types (lines and polys for example)
>
> - it's not supported
>
> Why not leverage the existing sp-fortify method by casting to Spatial?
>
> library(sf)
>
> ## from ?st_read
>
> nc <- st_read(system.file("shape/nc.shp", package="sf"), "nc", crs = 4267)
>
> ## a unique ID?
>
> length(unique(nc$NAME)) == nrow(nc)
> library(ggplot2)
> nc_f <- fortify(as(nc, "Spatial"), region = "NAME")
> ggplot(nc_f) + aes(x = long, y = lat, group = group, fill = id) +
> ggpolypath::geom_polypath() + guides(fill = FALSE)
>
>
> There are non-sp ways to do this, but none that are stable yet. Using
> ggpolypath ensures that holes will work, but if you don't need holes
> geom_polygon is fine.
>
> Let me know if you have problems getting what you want, but please provide
> reproducible examples.  It's not easy to navigate here, there are many
> traps and it's easy to get it wrong.
>
> (While the integrated  sf-ggplot2-geom will be awesome, it will be be
> embedded within a plot-only context, and I want those idioms available
> independently, and for going beyond simple features. )
>
> Cheers, Mike.
>
>
>
>
> --
> Edzer Pebesma
> Institute for Geoinformatics  (ifgi),  University of Münster
> Heisenbergstraße 2, 48149 Münster, Germany; +49 251 83 33081
> <+49%20251%208333081>
> Journal of Statistical Software:   http://www.jstatsoft.org/
> Computers & Geosciences:   http://elsevier.com/locate/cageo/
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
> --
> Dr. Michael Sumner
> Software and Database Engineer
> Australian Antarctic Division
> 203 Channel Highway
> Kingston Tasmania 7050 Australia
>
>         [[alternative HTML version deleted]]
>
> _______________________________________________
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo




-- 
*Manuel Spínola, Ph.D.*
Instituto Internacional en Conservación y Manejo de Vida Silvestre
Universidad Nacional
Apartado 1350-3000
Heredia
COSTA RICA
mspinola at una.cr <mspinola at una.ac.cr>
mspinola10 at gmail.com
Teléfono: (506) 8706 - 4662
Personal website: Lobito de río <https://sites.google.com/site/lobitoderio/>
Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>

	[[alternative HTML version deleted]]