docs: clarify version limitation with regional splits

Fixes #308

Author: elifclaus

R/get.R

@@ -52,7 +52,9 @@
 #'   directory index'). Note: the geographical coverage of an extract may
 #'   change over time. For example, recent (2021+) extracts for Barcelona are
 #'   at the regional level (cataluna), while older (2012-2021) extracts are at
-#'   the national level (spain).
+#'   the national level (spain). This means that downloading historical data
+#'   for a place like Barcelona may require changing the `place` argument to
+#'   "spain" for older versions.
 #' @param download_directory Directory to store the file containing OSM data?.
 #' @param force_download Should the `.osm.pbf` file be updated even if it has
 #'   already been downloaded? `FALSE` by default. This parameter is used to

vignettes/osmextract.Rmd

@@ -270,7 +270,7 @@ Finally, to reduce unnecessary computational resources and save bandwidth/electr
 
 ### Matching historical OSM extracts
 
-Starting from `osmextract` v0.5.2, the `version` argument can be used to match historical OSM extracts stored by Geofabrik provider. The default value is `"latest"` which corresponds to the most recent OSM extract. Other values can be specified using the format `"YYMMDD"`. The available extracts for each zone can be browsed from Geofabrik  [website](https://download.geofabrik.de/). Note that the geographical coverage of an extract may change over time. For example, recent (2021+) extracts for Barcelona are at the regional level (cataluna), while older (2012-2021) extracts are at the national level (spain).
+Starting from `osmextract` v0.5.2, the `version` argument can be used to match historical OSM extracts stored by Geofabrik provider. The default value is `"latest"` which corresponds to the most recent OSM extract. Other values can be specified using the format `"YYMMDD"`. The available extracts for each zone can be browsed from Geofabrik  [website](https://download.geofabrik.de/). Note that the geographical coverage of an extract may change over time. For example, recent (2021+) extracts for Barcelona are at the regional level (cataluna), while older (2012-2021) extracts are at the national level (spain). This means that downloading historical data for a place like Barcelona may require changing the `place` argument to "spain" for older versions.
 
 For example: