[GIS] Building web application to get PostGIS query from user and view result map using GeoServer via OpenLayers

geoserveropenlayers-2postgis

I'm a newbie in web-map application area.

I just found the small application in this tutorial interesting

I am a bit confused, because when I publish a map using GeoServer and OpenLayers, I have to create a layer in GeoServer first and this layer is fixed with a table from PostGIS and then use OpenLayers to call GeoServer to render the map.

How can the tutor of that tutorial change the data source of the layer depending on the query input by the users?
It means there are ways to change the data source of one layer on the fly right?

Please advice me how or can anyone tell me where can I download the code of the app in that tutorial.

Best Answer

You probably need to start at the very beginning to get your head around the basics of GeoServer first.

There is a good Question and Answer set available here on how to use GeoServer

Some good information on OpenLayers Tutorials can be found Here

and some interesting Tutorials on PostGis here

There is a lot of sample code that will help you in those reference ..

Related Solutions

OpenLayers – Adding Simple WFS Layer from GeoServer to OpenLayers Map

Take a look at my answer on this post.

Make sure your featureNS value is in the "Edit Workspace Page under Namespace URI" in your GEOSERVER. Do not use something as generic as "http://postgis.org". Use something like "http://yourdomain/application/catalogLayer" or something unique like that. You can make this URI up, just make it unique.

You have new BBOX() as a strategy but what do that box have as dimensions? I would change it to [new OpenLayers.Strategy.Fixed()] for testing.

featureType is not actually the type of geometry, it's your "Layer Name" in GEOSERVER (i know, misleading).

geometryName is the name of the field in your postgis database that has the Geometry data type. In GEOSERVER, Under "Edit Layer" you can see at the bottom "Feature Type details". There you will see a field with type "Geometry". Use the value under the property column

I would specify featurePrefix and version. Try something like this:

var wfs = new OpenLayers.Layer.Vector(
            "Stavros Features",
            {
                strategies: [new OpenLayers.Strategy.Fixed()]
                , projection: new OpenLayers.Projection("EPSG:4326")
                , protocol: new OpenLayers.Protocol.WFS({
                    version: "1.1.0",
                    url: "http://localhost:8081/geoserver/wfs",
                    featurePrefix: 'myWorkspace', //geoserver worspace name
                    featureType: "medford:parks", //geoserver Layer Name
                    featureNS: "http://medford.opengeo.org/medford", // Edit Workspace Namespace URI
                    geometryName: "bounds" // field in Feature Type details with type "Geometry"
                })
            });

[GIS] Help Setting up GeoServer Proxy with OpenLayers

well, it seems that the obvious was at play here. The 'text/plain' mimetype was the cause of the issue. Once i added this to GeoServer's proxy mimetypes and changed my proxy to be "localhost:80" then everything worked.

For future people seeing this post i tested it using JQuery. The GET request looks like this:

$.get("/geoserver/rest/proxy?url=localhost:80/myapp";, {format : 'text/plain'}, function(data){console.log(data); })

Best Answer

Related Solutions

OpenLayers – Adding Simple WFS Layer from GeoServer to OpenLayers Map

[GIS] Help Setting up GeoServer Proxy with OpenLayers

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