title: How do I convert a latitude/longitude pair into a PostGIS geography type?
body: <p>I'm trying to load a bunch of latitude/longitude pairs into a PostGIS geography type so as to be able to query by location. </p>
  
  <p>In particular I have a table with float latitude and longitude columns and a <code>geography(Point, 4326)</code> column. I would like to do</p>
  
  <pre><code>update mytable set geography = ???
  </code></pre>
  
  <p>The documentation appears to suggest that the following should work:</p>
  
  <pre><code>update mytable set geography = ST_GeogFromText('POINT(' || latitude || ' ' ||
                                                             longitude || ')');
  </code></pre>
  
  <p>It doesn't. I don't know what it's interpreting this point as meaning, but it only allows the longitude to lie between -90 and 90, so it's clearly not a longitude. </p>
  
  <p>So, what do I do? </p>