OpenLayers Zoom To Feature Help

Question

I have been struggling with something for a while that I figured would be simple. I have a WMS layer with many (millions) polygon features. This is a PostGIS layer (WMS). Each polygon has an ID in an attribute. I have a web page set up where a user can enter an ID and click a Search button. I would like the interface to find the polygon and zoom to it. With the research I have been doing, it appears I need to do this using a WMS layer. I have tried to import the layer as a WFS and it does not seem to be working.

My question is two part.

1) Do I need to do this with a WFS or can I stick with WMS?

2) Do you have any samples of code to do this with the data coming from this PostGIS store? I hate asking someone else to write the code, but if you can use what I put down below, that would be great just because I have been banging my head. I'm a .NET desktop programmer so this has been a learning curve.

Thanks for your help!

Answer 1

With a Million polygons, you really shouldn't use the WFS layer for Display. You should stick to the WMS Layer, since it comes as an image(so less data is transferred over the network), and less memory is consumed on the Client side.

Now coming to the search functionality. How are you doing the search? I guess the User enters the ID, and you want to zoom to the the polygon with that ID.

The best way to do this, is to have an empty vector layer in your OpenLayers Application Above your WMS layer, and send a WFS Get Feature Request like this:

http://example.com/geoserver/wfs?
service=wfs&
version=2.0.0&
request=GetFeature&
typeName=namespace:featuretype&
featureID=feature&
outputFormat=json

Once you get the geometry back, you can then zoom into the point, and add the selected polygon to the vector layer.