Changes introduced in PROJ 6, whether using the new proj.h API (sf) or the old proj_api.h API (rgdal, lwgeom) may impact R workflows and packages using sf or rgdal for transforming coordinate reference systems. Because +datum= is effectively defunct, and will be gone in PROJ 7 (March 2020), any data including CRS set correctly for previous PROJ will risk no longer be transformed correctly. Work is ongoing to establish how users can adapt to this, but it will be very risky to assume that transformations that worked in PROJ 4 will necessarily work as well or better in PROJ >= 6 without manual intervention. Discussion is welcomed, in particular on: https://github.com/r-spatial/discuss/issues/28 based on https://github.com/r-spatial/sf/issues/1146; further analysis described in the workshop document on https://rsbivand.github.io/geostat19_talk/. Please examine your workflows and packages, check whether your work is affected, and contribute to discussions through the issues on github. This list may be used, but it'll be best to keep things connected. Roger
Roger Bivand Department of Economics, Norwegian School of Economics, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; e-mail: Roger.Bivand at nhh.no https://orcid.org/0000-0003-2392-6140 https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en