A user on the GeoTools user list was trying to work out how to generate a full XML OGC Filter representation from a simpler CQL filter. The CQL filter could be used in a WFS Get request but when he switched to using Post requests he needed to use an OGC filter. While in some cases it is quite easy to convert a CQL filter in others this is a complex procedure. So I put together a quick GeoTools program to do the conversion for you.

package org.ianturton.cookbook.filters;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import org.geotools.filter.text.cql2.CQL;
import org.geotools.filter.text.cql2.CQLException;
import org.opengis.filter.Filter;

public class CQLToOGC {

public static void main(String[] args) throws IOException {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String line;
org.geotools.xml.Configuration configuration = new org.geotools.filter.v1_0.OGCConfiguration();
org.geotools.xml.Encoder encoder = new org.geotools.xml.Encoder(
configuration);
encoder.setIndenting(true);

while (!(line = reader.readLine()).isEmpty()) {
try {
Filter filter = CQL.toFilter(line);
// System.out.println("\t" + filter);
encoder.encode(filter, org.geotools.filter.v1_0.OGC.Filter, System.out);
} catch (CQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

}

It just reads standard in until it gets a blank line. It then writes the XML out to standard out. I’m an old school UNIX user.

So typing:

prop = 23

gives a result of:`

<?xml version="1.0" encoding="UTF-8"?><ogc:Filter xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ogc="http://www.opengis.net/ogc" xmlns:gml="http://www.opengis.net/gml">
<ogc:PropertyIsEqualTo>
<ogc:PropertyName>prop</ogc:PropertyName>
<ogc:Literal>23</ogc:Literal>
</ogc:PropertyIsEqualTo>
</ogc:Filter>

or

INTERSECTS(SP_GEOMETRY, POLYGON ((142578.64599609 252217.79003906, 73781.897460938 141983.61767578, 287078.38037109 146764.85888672, 142578.64599609 252217.79003906)))

gives a result of:

<?xml version="1.0" encoding="UTF-8"?>
<ogc:Filter xmlns:ogc="http://www.opengis.net/ogc" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:gml="http://www.opengis.net/gml">
<ogc:Intersects>
<ogc:PropertyName>SP_GEOMETRY</ogc:PropertyName>
<gml:Polygon>
<gml:outerBoundaryIs>
<gml:LinearRing>
<gml:coordinates>142578.64599609,252217.79003906 73781.897460938,141983.61767578 287078.38037109,146764.85888672 142578.64599609,252217.79003906</gml:coordinates>
</gml:LinearRing>
</gml:outerBoundaryIs>
</gml:Polygon>
</ogc:Intersects>
</ogc:Filter>