list_map admin attr could take a callable -- feature request

[skyl]

I did this in my branch; I don't like the solution but it works. I can make a branch and commit the change if you are interested. The reason this is important is you can use the http://geodjango.org/docs/geos.html#simplify-tolerance-0-0-preserve-topology-false so when you have 600 very complicated polygons you can render them without crippling the browser.

def get_changelist_map(self, cl):
    """
    Display a map in the admin changelist, with info popups
    """
    if self.list_map:
        info = []
        for obj in cl.get_query_set():
            # Transform the fields into one projection.
            try:
                geoms = [getattr(obj, field) for field in self.list_map]
                for geom in geoms:
                    geom.transform(int(DEFAULT_PROJ))
            except AttributeError:
                geoms = [getattr(obj, field)() for field in self.list_map]
                for geom in geoms:
                    geom.transform(int(DEFAULT_PROJ))

[yourcelf]

Hmmm, I see your point, this could be useful. Of course, you could just subclass GeoModelAdmin with this implementation... but I can see it being useful, in general, to support fields and callables.

I agree that the solution seems a little inelegant. I'll think on it and see if I can come up with another way. Let me know if you think of one.

[yourcelf]

Hey,

I've implemented this in the latest master in the following way:

def get_changelist_map(self, cl):
    """ 
    Display a map in the admin changelist, with info popups
    """
    if self.list_map:
        info = []
        for obj in cl.get_query_set():
            # Transform the fields into one projection.
            geoms = []
            for field in self.list_map:
                geom = getattr(obj, field)
                if callable(geom):
                    geom = geom()
                geoms.append(geom)
            for geom in geoms:
                geom.transform(int(DEFAULT_PROJ))

Let me know if you encounter any trouble with this implementation.