How to pass properties to the geojsonfeature filter

[capooti]

Hi, I cannot figure out how to pass the properties parameter to the geojsonfeature filter.

With GeoJSONLayerView in urls.py this is easy:

    GeoJSONLayerView.as_view(model=MyModel,
        properties=(
            ['field1', 'field2',]
        )),
        name='myname')

But for my use case I need to filter the model, that's why I have created a view like this:

def mymodel_geojson(request):
object_list = MyModel.objects.all().filter(some_filter_here)
properties= ['field1', 'field2',]
return render_to_response(
'myapp/mytemplate.geojson',
{
'object_list': object_list,
'properties': properties,
}, )

Now in my template, how do I pass the parameters?

{% load geojson_tags %}

{{ object_list|geojsonfeature:"???" }}

According to this it should not be possible to create a filter accepting multiple parameters:
http://stackoverflow.com/questions/420703/how-do-i-add-multiple-arguments-to-my-custom-template-filter-in-a-django-templat

thanks for the great library!

[capooti]

I ended up using an inherited generic views, redefining the get_queryset method to return the desired queryset.
Though, still curious about how to pass the parameters to the geojsonfeature filter.

[leplatrem]

Hi !

It looks like you're confused between the view (serving GeoJSON) and the template filter (embedding GeoJSON within an HTML template).

So, if you need to serve GeoJSON with some properties, just add this in urls.py :

 GeoJSONLayerView.as_view(model=MyModel, properties=('field1', 'field2'), name='myname')

But if you need to embed some GeoJSON within an HTML page (less common to be honest), you may be right, the many parameters are maybe useless ! I will open another issue for that :)

[capooti]

Hi, no I am not confused :) I exactly did what you suggested in urls.
I had then to use the generic view approach and redefine the get_queryset as I did not find a different way to pass a filtered query set.
My question here is: how to pass the parameters to the geojsonfeature filter? Thanks in advance.

[capooti]

This is the code I used:

views.py

class MyModelLayer(GeoJSONLayerView):
    def get_queryset(self):
        context = MyModel.objects.all().filter(...some_filter_here...)
        return context

urls.py

url(r'^data/mymodel.geojson$', 
    MyModelLayer.as_view(model=MyModel,
        properties=(
            ['field1', 'field2',]
        )),
        name='mymodel-geojson'),

[leplatrem]

Ok, great, indeed a filtered queryset like this should work.

Regarding the other question: so far it looks like the template filter geojsonfeature does not allow parameters (see issue #16). Why do you need it for ?

[capooti]

because according to this:
https://github.com/makinacorpus/django-geojson/blob/master/djgeojson/templatetags/geojson_tags.py#L17

we may pass the following parameters to the filter:

def geojsonfeature(source, geometry_field='geom', properties=None, srid=GEOJSON_DEFAULT_SRID)

but cannot figure out how to pass the properties and srid parameters (it looks like a Django filter will accept just one parameter from template).
The only way I can figure out to use this filter if you need to modify its parameters is by inheriting from it and change the parameters in the inherited filter.
Is this the intended behaviour?
Regards

[leplatrem]

Yes indeed, this part of the code was written in a way that cannot be used :D (purpose of issue #16)

We could specify only one parameter as string (split on :)

 {{ object|geojsonfeature:"name,age" }}
 {{ object|geojsonfeature:"name:geom" }}
 {{ object|geojsonfeature:"title,description:geom:2154" }}
 {{ object|geojsonfeature:":geom:4326" }}

[capooti]

+1, thanks :)