[OpenLayers-Users] Make vector layer from JSON
Sveen Atle Frenvik (Geomatikk IKT)
Atle.Frenvik.Sveen at geomatikk.no
Mon Mar 8 07:32:04 EST 2010
As long as you are able to parse the data, putting them on the map is a
no-brainer, pseudo-code something like:
for each feature
- fetch x and y
- create an OpenLayers Geometry
- create a OpenLayers Vector feature
- add attributes to feature if required
then add features to a layer
-atle
On 03/08/2010 01:19 AM, Stephen Woodbridge wrote:
> Hi Guys,
>
> I have been looking into a similar problem using some arbitrary XML and
> have some questions on how to do this also that I will post in a
> separate thread, but here is my take on what needs to be done.
>
> OpenLayers.Format.JSON should handle the actual parsing and give you a
> top level variable for the obj.
>
> I think what you need to do is implement your own read function or
> callback, that should get the parsed JSON file and then you create the
> features and add them to the layer.
>
> So this is all in theory at the moment, because I haven't been able to
> figure out the exact steps for doing it in my own project. But since I
> have looked at a similar problem all day I think this is the approach.
>
> So I think in your code below you need to do something like:
>
> var data = json.read(resp);
> var features = myMakeFeatures(data);
>
> then add the features to the layer.
>
> -Steve W.
>
> Arnd Wippermann wrote:
>
>> Hello Robert,
>>
>> I don't know ArcGis Server, but I would look, if you can get your data
>> in gml or kml. Otherwise you have to write your own parser.
>>
>> Arnd
>>
>> ------------------------------------------------------------------------
>> *Von:* Robert Sanson [mailto:SansonR at asurequality.com]
>> *Gesendet:* Sonntag, 7. M�rz 2010 21:09
>> *An:* 'Hugo'; Arnd Wippermann
>> *Cc:* users at openlayers.org
>> *Betreff:* Re: [OpenLayers-Users] Make vector layer from JSON
>>
>> I am wrestling with a similar problem. I am trying to read in data
>> coming from an ArcGIS Server in JSON format. Unfortunately, ArcGIS
>> Server doesn't serve GeoJSON. Here is a sample of what the data looks like:
>>
>> {
>> "results" : [
>> {
>> "layerId" : 0,
>> "layerName" : "Main_Gates",
>> "displayFieldName" : "road_name",
>> "foundFieldName" : "farm_id",
>> "value" : "AS00136",
>> "attributes" : {
>> "point_location_id" : "232495",
>> "farm_id" : "AS00136",
>> "rapid_no" : "104",
>> "road_name" : "Winslow Willowby Rd",
>> "locality" : "Null",
>> "x_nztm" : "1492934.61",
>> "y_nztm" : "5131545.29",
>> "Shape" : "Point"
>> },
>> "geometryType" : "esriGeometryPoint",
>> "geometry" :
>> {
>> "x" : 1492934.61,
>> "y" : 5131545.29,
>> "spatialReference" : {
>> "wkid" : 2193
>> }
>> }
>> }
>> ]
>> }
>> Any ideas how to get OL to read this into a Vector layer?
>>
>> Thanks,
>>
>> Robert
>> >>> "Arnd Wippermann"<arnd.wippermann at web.de> 7/03/2010 10:43 a.m.>>>
>> Hi,
>> i would think, that you have to use geojson instead of json, to get the
>> geometry for the features.
>> Arnd
>>
>> ------------------------------------------------------------------------
>> *Von:* users-bounces at openlayers.org
>> [mailto:users-bounces at openlayers.org] *Im Auftrag von *Hugo
>> *Gesendet:* Samstag, 6. M�rz 2010 19:14
>> *An:* openlayers
>> *Betreff:* [OpenLayers-Users] Make vector layer from JSON
>>
>> Hello all,
>>
>> I'm trying to create a vector layer based on a php query (which includes
>> the_geom) encoded in JSON. Until the moment i haven't been able to
>> achieve this.
>> Following, is the relevant part of the code:
>>
>> var connect = new Ext.data.Connection();
>> connect.request({
>> url: 'mfbase/geoquery.php',
>> params: {
>> species: species,
>> datai: datai,
>> dataf: dataf
>> },
>> success: function(response){
>> var resp = response.responseText;
>> var json = new OpenLayers.Format.JSON();
>> var data = json.read(resp);
>> //console.log(data[0].the_geom);
>>
>> var querylayer1 = new OpenLayers.Layer.Vector(
>> 'Query1',
>> {
>> isBaseLayer: false,
>> projection: wgs,
>> geometryName: 'the_geom',
>> }
>> );
>>
>> querylayer1.addFeatures(data);
>> map.addLayer(querylayer1);
>> }
>> })
>>
>> Any suggestions are more than welcomed :)
>> Thanks to you all!
>>
>> Cheers,
>>
>>
>> --
>> Hugo Martins
>> FMV-UTL
>> CIISA-Epidemiologia e Sa�de P�blica Veterin�ria
>> Av. da Universidade T�cnica
>> 1300-477 Lisboa
>> N 38�42'49.54", W 9�11'43.42"
>>
>>
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>>
>>
>>
>>
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--
Atle Frenvik Sveen
GIS Konsulent
Geomatikk IKT AS
tlf: 45 27 86 89
atle.frenvik.sveen at geomatikk.no
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