<div id="docs-body">
 <div class="section">
  <div class="titlepage">
   <div>
    <div>
     <h3 class="title">
      <a name="gis-property-functions">
      </a>
      14.16.7 Geometry Property Functions
     </h3>
    </div>
   </div>
  </div>
  <div class="toc">
   <dl class="toc">
    <dt>
     <span class="section">
      <a href="gis-general-property-functions.html">
       14.16.7.1 General Geometry Property Functions
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="gis-point-property-functions.html">
       14.16.7.2 Point Property Functions
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="gis-linestring-property-functions.html">
       14.16.7.3 LineString and MultiLineString Property Functions
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="gis-polygon-property-functions.html">
       14.16.7.4 Polygon and MultiPolygon Property Functions
      </a>
     </span>
    </dt>
    <dt>
     <span class="section">
      <a href="gis-geometrycollection-property-functions.html">
       14.16.7.5 GeometryCollection Property Functions
      </a>
     </span>
    </dt>
   </dl>
  </div>
  <p>
   Each function that belongs to this group takes a geometry value as
      its argument and returns some quantitative or qualitative property
      of the geometry. Some functions restrict their argument type. Such
      functions return
   <code class="literal">
    NULL
   </code>
   if the argument is of an
      incorrect geometry type. For example, the
   <a class="link" href="gis-polygon-property-functions.html#function_st-area">
    <code class="literal">
     ST_Area()
    </code>
   </a>
   polygon function returns
   <code class="literal">
    NULL
   </code>
   if the object type is neither
   <code class="literal">
    Polygon
   </code>
   nor
   <code class="literal">
    MultiPolygon
   </code>
   .
  </p>
 </div>
 <br/>
</div>
