title: python postgis ST_ClosestPoint
body: <p>I am struggling with an SQL command issued from my python script. Here is what I have tried so far, the first example works fine but the rest do not.</p>
  
  <pre><code>#working SQL = "SELECT ST_Distance(ST_Transform(ST_GeomFromText(%s, 4326),27700),ST_Transform(ST_GeomFromText(%s, 4326),27700));"
  #newPointSQL = "SELECT ST_ClosestPoint(ST_GeomFromText(%s),ST_GeomFromText(%s));"
  #newPointSQL = "SELECT ST_As_Text(ST_ClosestPoint(ST_GeomFromText(%s), ST_GeomFromText(%s)));"
  #newPointSQL = "SELECT ST_AsText(ST_ClosestPoint(ST_GeomFromEWKT(%s), ST_GeomFromText(%s)));"
  #newPointSQL = "SELECT ST_AsText(ST_Line_Interpolate_Point(ST_GeomFromText(%s),ST_Line_Locate_Point(ST_GeomFromText(%s),ST_GeomFromText(%s))));"
  
  newPointData = (correctionPathLine,pointToCorrect) - ( MULTILINESTRING((-3.16427109855617 55.9273798550064,-3.16462372283029 55.9273883602162)), POINT(-3.164667 55.92739)) 
  </code></pre>
  
  <p>My data is picked up ok because the first sql is successfull when executed. The problem is when I use the ST_ClosestPoint function.
  Can anyone notice a misuse anywhere? Am I using the ST_ClosetsPoint in a wrong way? 
  In the last example, I did modify my data (in case someone notices) to run it but it still would not execute. </p>