Roger Bivand: Coordinate Reference Systems
Talk by Roger Bivand, Professor Emeritus, Norwegian School of Economics, at the University of Chicago's Center for Spatial Data Science (Jan. 19, 2023).
https://rsbivand.github.io/csds_jan23...
The FOSS ecosystem is very dependent on the PROJ library, which has changed a great deal since PROJ.4. PROJ 5 introduced transformation pipelines, PROJ 6 an SQLite database of CRS, transformations, etc., and upgraded CRS representation from the legacy PROJ.4 string to WKT2-2019. PROJ 7 introduced a content download network for accessing transformation grids. We are now at PROJ 9.1.1. GDAL 3 requires PROJ 6 or greater, and is now tightly integrated with PROJ. In addition, modern vector file formats such as GeoPackage assume a basic geographical CRS where none is given, so we need to innovate to express a missing planar CRS.
CORRECTION: Please refer to the post-workshop note in https://rsbivand.github.io/csds_jan23..., which explain why the discrepancy between NAD27 and NAD84 (HARN) for Chicago appears too small in the talk.