How transform geometry column using GeoDjango

[Shoaib Ijaz]

I am trying to transform geometry column in django, here is my model

class Network(models.Model):
    name = models.CharField(max_length=50, blank=True)
    alias = models.CharField(max_length=100, blank=True)
    geometry = models.GeometryField(srid=3857, null=True, blank=True)
    bbox = models.GeometryField(srid=3857, null=True, blank=True)
    objects = models.GeoManager()

    class Meta:
        db_table = u'tbl_network'

    def __unicode__(self):
        return '%s' % self.name

I am trying to transform bbox column but GeoQuerySet automatically tranform geometry column

Network.objects.transform(srid=3857).values('geometry','bbox')

SQL query output of above django query

  SELECT ST_Transform("tbl_network"."geometry", 3857), "tbl_network"."bbox" FROM "tbl_network"

So i tried it different way, now i exclude geometry column

 Network.objects.transform(srid=3857).values('bbox')

SQL query output of above django query

 SELECT "tbl_network"."bbox" FROM "tbl_network"

Now GeoQuerySet totally ignore transform function.

So my questions is,

How can i transform specific column of model?