title: Orion Context broker - query
body: <p>In version 0.23 of Orion context broker.</p>
  
  <p>Can I query the context for entities with a certain value on an attribute? How?</p>
  
  <p>Can I query for entities generated at a certain time range? How?</p>
  
  <p>For geolocation Filter. Is there any limit to the polygon vertices besides request size of 1MG?</p>
  
  <p>thanks</p>