updating bivand progress to 2021

01-introduction.Rmd

@@ -356,7 +356,7 @@ New ideas about spatial data representations were also being developed in this p
 \index{lidR (package)}
 It includes the **stars** package, closely connected to **sf**, for handling raster and vector data cubes [@pebesma_stars_2021] and **lidR** for processing of airborne LiDAR (Light Detection and Ranging) point clouds [@Roussel2020].
 
-This modernization had several reasons, including the emergence of new technologies and standard, and the impacts from spatial software development outside of the R environment [@bivand_progress_2020].
+This modernization had several reasons, including the emergence of new technologies and standard, and the impacts from spatial software development outside of the R environment [@bivand_progress_2021].
 The most important external factor affecting most spatial software, including R spatial packages, were the major updates, including many breaking changes to the PROJ library\index{PROJ} that had begun in 2018.
 Most importantly, these changes forced the replacement of `proj4string` to `WKT2` representation for storage of coordinate reference systems and coordinates operations (learn more in Section \@ref(crs-intro) and Chapter \@ref(reproj-geo-data)).
 

02-spatial-data.Rmd

@@ -938,7 +938,7 @@ In the past, the `proj4string` definitions, was the standard way to specify coor
 These string representations, built on a key=value form (e.g, `+proj=longlat +datum=WGS84 +no_defs`), are, however, currently discouraged in most cases.
 PROJ version 6 and further still allows to use `proj4string`s to define coordinate operations, but some `proj4string` keys are no longer supported or are not advisable to use (e.g., `+nadgrids`, `+towgs84`, `+k`, `+init=epsg:`) and only three datums (i.e., WGS84, NAD83, and NAD27) can be directly set in `proj4string`.
 Importantly, `proj4string`s are not used to store CRSs anymore.
-Longer explanations on the recent changes in the PROJ library and why `proj4string` was replaced by `WKT2` can be found in @bivand_progress_2020, Chapter 2 of @pebesma_spatial_2022, and [blog post by Floris Vanderhaeghe](https://inbo.github.io/tutorials/tutorials/spatial_crs_coding/).
+Longer explanations on the recent changes in the PROJ library and why `proj4string` was replaced by `WKT2` can be found in @bivand_progress_2021, Chapter 2 of @pebesma_spatial_2022, and [blog post by Floris Vanderhaeghe](https://inbo.github.io/tutorials/tutorials/spatial_crs_coding/).
 
 Let's look at how CRSs are stored in R spatial objects and how they can be set.
 For this, we need to read-in a vector dataset:

geocompr.bib

@@ -156,7 +156,7 @@ @inproceedings{bivand_open_2000
   keywords = {\#nosource,⛔ No DOI found}
 }
 
-@article{bivand_progress_2020,
+@article{bivand_progress_2021,
   ids = {bivand_progress_2020a,bivand_progress_2021},
   title = {Progress in the {{R}} Ecosystem for Representing and Handling Spatial Data},
   author = {Bivand, Roger S.},