Satsymph Hermes - interrogating google map API markers

aF_createPerimeterFromMarkers.js

function createPerimeterFromMarkers()
{
  /*
     1. interrogate the named elements in our named frame
        (containing a google map API with four user-droppable markers)

     2. create an AppFurnace Geo Line object using the four co-ordinates
        indicated by the user in the google map API frame
  */

  // references to the screen and frame
  var scr = Screens.getScreen( 'index' );
  var frame = scr.getIFrameElement( 'myIFrame' );
  var actualFrame = document.getElementById('calMyIFrameSubframe');    
  
  // reference to the document in the named frame
  var aFDoc = (actualFrame.contentWindow || actualFrame.contentDocument);
  if (aFDoc.document){ aFDoc = aFDoc.document; }
    
  /*
   interrogate the named DIV elements
   if any of the elements are blank - pop up an alert and abort!
  */  
  for (var i=1; i<=4; i++)
  {
    var markerLat = aFDoc.getElementById('m' + i + 'lat').innerHTML;
    var markerLng = aFDoc.getElementById('m' + i + 'lng').innerHTML;
    
    // abort if the marker is not set
    if ( markerLat == '' || markerLat === null || markerLat === undefined 
      || markerLng == '' || markerLng === null || markerLng === undefined)
    {
      var errorMessage = 'You must set all 4 markers. (marker ' + i + ' is not set)';
      Debug.log(errorMessage);
      alert('error', errorMessage);
      return;
    }
    else
    {
      markerLat = parseFloat( markerLat );
      markerLng = parseFloat( markerLng );
      var currentCoord = new Coord( markerLng, markerLat, cal.Coord.Datum.WGS84 );
      
      var userPerimeterLine = null;
      if ( i == 1 ) 
      {  
        Debug.log('first point');
        
        // workaround bug that line constructor requires two points
        // solution: add two identical points!
        userPerimeterLine = 
                new Line("userPerimeterLine", [currentCoord, currentCoord]);
        GeoFeatures.addFeature(userPerimeterLine);
        
        // modify the object added to geo features to be visible
        // question: not sure if this could be done to the var userPerimeterLine
        GeoFeatures.getFeatureByName( "userPerimeterLine" ).setShapeVisible( true );
      }
      else
      {
        userPerimeterLine = GeoFeatures.getFeatureByName("userPerimeterLine");
        userPerimeterLine.addNode( currentCoord );
      }
    }// else marker lat/lng is valid
  }// for each marker
}