Question

I would like to have “realtime” like map.

My main question is:

• How to use django-olwidget with openlayers OpenLayers.Strategy.Refresh?

  Do I need to start back “from scratch” to use manually openlayers?

  With django-olwidget, the data is on the web page so the args which define data-source, protocol.

My “second” question is about which format should I choose…

• geoJSON? kml? other?

  Can those formats contain openlayers point specific “style” specifications like:

  {'graphic_name': 'square', 'point_radius': 10, 'fill_color': "#ABBAAB', 'stroke_color':'#BAABBA'}.

I already overriden the default map template olwidget/multi_layer_map.html to access my map object in JS. I think it should be rather simple to apply a js function on each data layers before passing it to the map.

Thanx in advance.

PS: I’m french speaker.

PS2: I asked this question as a feature request on github: https://github.com/yourcelf/olwidget/issues/89

Answer 1

If you’re going to use regularly-refreshing data (without refreshing the page) and serialization formats like geoJSON and KML, django-olwidget won’t help you very much out of the box. You might find it easier just to use OpenLayers from scratch.

But if you really wanted to use django-olwidget, here’s what I would do:

1. Subclass olwidget.InfoLayer to create a new vector layer type that uses a network-native format like geoJSON or KML to acquire its data.
2. Add a corresponding python subclass to be able to use it with Django forms or whatever the use case is. You’ll probably need to specify things like the URL from which the map will poll its data.

This is a lot of work beyond writing for OpenLayers directly. The advantages would be that you would get easy Django form integration with the same map.

As to which serialization format to use: I’m partial to JSON flavors over XML flavors such as KML, but it really doesn’t matter much — Django and OpenLayers both speak both fluently.