geoserver cql_filter

CQL (Common Query Language) filter is a feature in GeoServer that allows you to define filters for querying spatial data. It allows you to specify conditions to select specific features that meet certain criteria.

To apply a CQL filter in GeoServer, you can use the `cql_filter` parameter in the URL when making requests to the WFS (Web Feature Service) or WMS (Web Map Service) endpoints. Here's an example of how to use it:

1. For WFS:

   http://your-geoserver-url/wfs?request=GetFeature&typename=your-layer-name&cql_filter=your-filter-expression

Replace `your-geoserver-url` with the actual URL of your GeoServer, `your-layer-name` with the name of the layer you want to filter, and `your-filter-expression` with the CQL expression defining your filter.

2. For WMS:

   http://your-geoserver-url/wms?request=GetMap&layers=your-layer-name&cql_filter=your-filter-expression

Similar to the WFS example, replace the placeholders with the appropriate values.

The `cql_filter` parameter accepts CQL expressions that can include comparison operators, logical operators, and functions. For example, you can use `property_name = value` or `property_name LIKE 'pattern'` to filter based on attribute values.

Make sure to properly encode the CQL expression if it contains special characters or spaces.

I hope this helps! Let me know if you have any further questions.