Add WKT2 CRS representation to example data

[jcheng5]

I received an email from Roger Bivand via CRAN:

Dear maintainer,

Your package leaflet stores data objects using classes defined
in the sp package or inheriting from those classes. From sp 1.4-* and
rgdal 1.5-*, CRS objects are now expected to have a comment containing
an WKT2 CRS representation - see:

https://www.r-spatial.org/r/2020/03/17/wkt.html

A section at the foot of

https://rgdal.r-forge.r-project.org/articles/CRS_projections_transformations.html#rebuilding-crs-objects

describes possible steps for updating CRS objects; earlier sections cover
background issues. Working around sp objects with stale CRS is already
causing difficulties, so your cooperation in upgrading will be helpful.An attempt has been made to rebuild data objects using sp::rebuild_CRS(),
and output (re-stored as version 2) may be found on my server at:

http://spatial.nhh.no/R/rebuilt_sp_objects/

The functions used are from the development version of rgdal, 1.5-17,
rev >= 1053, use:

install.packages("rgdal", repos="http://R-Forge.R-project.org")

and:

remotes::install_github("rsbivand/sp")

should you wish to make changes. Please check carefully that these objects
are as you would expect. Note that the rebuilt CRS object contains
a revised version of the input Proj4 string as well as the WKT2 string,
and may be used with both older and newer versions of sp. Objects
inheriting from sp classes but with NA CRS are not modified.

Minimal reproducible example

library(leaflet)
comment(atlStorms2005@proj4string)
comment(breweries91@proj4string)
comment(gadmCHE@proj4string)

I can confirm that with the new .rda files provided by Roger, these calls return WKT2 strings, while the old copies do not. I also tried using these objects with leaflet and everything works fine.

PR task list:

• Update NEWS
• Add tests (where appropriate)
  • R code tests: tests/testthat/
  • Visual tests: R/zzz_viztest.R
• Update documentation with devtools::document()

[jcheng5]

Something is wrong with the data, our unit tests convert them from sp to sf and it's throwing errors. I have an email out to Roger asking for guidance.

Edit: Roger figured it out, was due to a combination of a buglet in sf and my system's old GDAL/PROJ libraries.

[jcheng5]

Tests are warning, e.g.:

test-normalize-2.R:24: warning: normalize
sf layer has inconsistent datum (+proj=longlat +ellps=WGS84 +towgs84=0,0,0,0,0,0,0 +no_defs ).
Need '+proj=longlat +datum=WGS84'

Relates to #505, r-spatial/mapview#72. In #505, I promised to get back to the question of automatically transforming sp/sf input after the next CRAN release, but never did. This could be the right time to do it.

[tim-salabim]

@jcheng5 what's your take here? Should leaflet do on-the-fly projection or not? It's of course convenient for the user, but somewhat questionable from an educational point of view (from my experience as a geodata scientist).

[jcheng5]

Rebased against master and force-pushed, to pick up the change from Travis to GitHub Actions, and dropped the Remotes field as the sf we need is on CRAN.

[jcheng5]

This seems to work fine now, I think the sf update fixed the warnings.