title: Trigger NOTIFY only on points that are in a certain PostGIS region
body: <p>I would like to trigger <code>NOTIFY</code> only on points that are in a certain <code>PostGIS</code> region. I have a table called <code>car</code>. I want to get a <code>NOTIFY</code>cation every time a car updates it's coordinate or a new car is updated, but only in a certain region. Essentially I want to monitor for changes in rows that have a point that is located in the region of my interest.</p>
  <p>I would be grateful for any hints in the right direction. Thank you in advance.</p>