Add ASDAR 2ed comment description to help page

[rsbivand]

ASDAR 2d, pp. 47-48 description needed in sp help pages and link to rgeos for analysing exterior/interior (pp. 132-133). Still not guaranteed to be valid because shapefiles treat interior rings touching exterior rings differently.

[rsbivand]

Ping @rsbivand @mdsumner

[edzer]

library(sp)
?Polygons

and search for "comment"; see also sf/R/sp.R, and search for comment.

[mdsumner]

thanks, I see it's documented in rgeos::createSPComment also on rforge only, but can be browsed on the read-only github rforge mirror at https://github.com/rforge/rgeos/blob/master/pkg/man/comment-functions.Rd

[rsbivand]

The github mirror is useless, not supported by the maintainer, so by definition not where to go. Read the package help page at https://cran.r-project.org/package=rgeos, and find the maintainer-provided documentation site at http://rgeos.r-forge.r-project.org/index.html where http://rgeos.r-forge.r-project.org/reference/comment-functions.html provides the online version of ?createSPcomment.