Reduce the components of an osmdata object to only unique items of
each type. That is, reduce $osm_points to only those points not
present in other objects (lines, polygons, etc.); reduce $osm_lines to
only those lines not present in multiline objects; and reduce
$osm_polygons to only those polygons not present in multipolygon
objects. This renders an osmdata object more directly compatible with
typical output of sf.
unique_osmdata(dat)An osmdata object
Equivalent object reduced to only unique objects of each type