1 from django.db.models import Aggregate

     2 from django.contrib.gis.db.models.sql import GeomField

     3 

     4 class Collect(Aggregate):

     5     name = 'Collect'

     6 

     7 class Extent(Aggregate):

     8     name = 'Extent'

     9 

    10 class Extent3D(Aggregate):

    11     name = 'Extent3D'

    12 

    13 class MakeLine(Aggregate):

    14     name = 'MakeLine'

    15 

    16 class Union(Aggregate):

    17     name = 'Union'