A shapefile (.shp) can be used to define a set of features of interest
(e.g. the location of trees). Notice that the shapefile must contain
a set of Point geometries.
Besides the '.shp' file the files '.dbf' and '.prj' can also be selected.
The assumed projection is WGS84, so if the data uses
another coordinate reference system it is important
to provide a '.prj' file with
the proper PROJ or WKT string.