<?xml version="1.0"?>
<fes:Filter
   xmlns:fes="http://www.opengis.net/fes/2.0"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://www.opengis.net/fes/2.0 http://schemas.opengis.net/filter/2.0/filterAll.xsd">
   <fes:PropertyIsEqualTo>
      <fes:Function name="SIN">
         <fes:ValueReference>DISPERSION_ANGLE</fes:ValueReference>
      </fes:Function>
      <fes:Literal>1</fes:Literal>
   </fes:PropertyIsEqualTo>
</fes:Filter>