Fix issue, define 'sticky'

02-spatial-data.Rmd

@@ -187,7 +187,7 @@ summary(world["lifeExp"])
 ```
 
 Although we have only selected one variable for the `summary` command, it also outputs a report on the geometry such as its `MULTIPOLYGON` geometry type.
-This is due to the sticky behavior of the geometry columns of **sf** objects (see Chapter \@ref(attr)).
+This demonstrates the 'sticky' behavior of the geometry columns of **sf** objects, meaning the geometry is kept unless the user deliberately removes them, as we'll see in section \@ref(vector-attribute-manipulation).
 Hence, the result provides a quick summary of both the non-spatial and spatial data contained in `world`: the average life expectancy is 73 years (ranging from less than 50 to more than 80 years) across all countries which are represented in the form of `MULTIPOLYGON` geometries.
 `MULTIPOLYGON` geometries allow more than one polygon per row (here: country).
 This representation is necessary for countries with many islands such as Indonesia and Greece.