[Users] Best way to enter feature properties using a json server backend?

[Matt Priour]

If you are going to be creating valid GeoJSON from geoDjango then just use the OpenLayers.Format.GeoJSON format reader. If you are just getting JSON with some non-GeoJSON mix of attributes and geo properties, then you will need to write a function to parse the output of OpenLayers.Format.JSON into OpenLayers.Feature objects. The best practice in that case would be to actually sub-class the OpenLayers.Format.JSON parser into your custom parser, but you could also just do that function in your application logic.

To handle requests to the server, I would recommend using a GeoExt.data.FeatureStore with a GeoExt.data.ProtocolProxy created from an OpenLayers.Layer.Vector with an HTTP protocol. Here is an example:

var vectorLyr = new OpenLayers.Layer.Vector('layer',{
protocol: new OpenLayers.Protocol.HTTP({
                  url: 'http://myserver.com/geo',
                  format: new OpenLayers.Format.GeoJSON()
              })
});

var featStore = new GeoExt.data.FeatureStore({
fields:['foo',{name:'bar',type:'int'}],
proxy:new GeoExt.data.ProtocolProxy({protocol:vectorLyr.protocol})
});

now you can hook the feature store up to a grid or other data view, etc... 
You can use normal Ext.data.Store load methods and options to update the store or you can go the other way and use an OpenLayers.Strategy within the vector layer to have it reload itself at appropriate times.

Matt Priour


From: Andrew Parker 
Sent: Thursday, February 03, 2011 7:56 AM
To: users at geoext.org 
Subject: [Users] Best way to enter feature properties using a json server backend?


Hello Mike:

I am planning to do the same thing as you, however, you are a month 
ahead of me.  My initial plan is to use geodjango to obtain attribute 
data from a postGIS database and feed it back to GeoEXT/OpenLayers via JSON.

I do not yet know how to do this but I thought this may give you some 
ideas how to proceed.  Perhaps we can work together to figure this out?

-- 
Andrew Parker
Source3 Computing, LLC



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