Google Earth API Samples - Setting Feature Opacity

WARNING: This feature is currently experimental.

Relevant Resources:

• KmlFeature Reference

Relevant Code Excerpt:

<!-- Very basic slider -->
<script src="static/simple-slider.js" type="text/javascript"></script>
<link href="static/simple-slider.css" type="text/css" rel="stylesheet"/>

var folder;
var groundOverlay;
var lineStringPlacemark;
var pointPlacemark;

// make the slider for dragging the tour timeline
var slider = new SimpleSlider(document.getElementById('slider-container'), {
  onSlide: function(pos) {
    if (folder)
      folder.setOpacity(pos);
  },
  max: 1.0,
  startPosition: 1.0,
  formatPosFn: function(pos) { return Math.floor(100 * pos) + '%'; }
});

var la = ge.getView().copyAsLookAt(ge.ALTITUDE_RELATIVE_TO_GROUND);
la.setRange(200000);
la.setHeading(45);
la.setTilt(45);
ge.getView().setAbstractView(la);

// Create a folder to contain various features.
folder = ge.createFolder('');

groundOverlay = ge.createGroundOverlay('');
groundOverlay.setIcon(ge.createIcon(''))
groundOverlay.getIcon().setHref("http://www.google.com/intl/en_ALL/images/logo.gif");
groundOverlay.setLatLonBox(ge.createLatLonBox(''));

var center = ge.getView().copyAsLookAt(ge.ALTITUDE_RELATIVE_TO_GROUND);
var north = center.getLatitude() + .35;
var south = center.getLatitude() - .35;
var east = center.getLongitude() + .55;
var west = center.getLongitude() - .55;
var rotation = 0;
var latLonBox = groundOverlay.getLatLonBox();
latLonBox.setBox(north, south, east, west, rotation);
folder.getFeatures().appendChild(groundOverlay);

// Create a point placemark.
pointPlacemark = ge.createPlacemark('');
pointPlacemark.setName('Hello World');

var style = ge.createStyle('');
var icon = ge.createIcon('');
icon.setHref('http://maps.google.com/mapfiles/kml/paddle/red-circle.png');
style.getIconStyle().setIcon(icon);
pointPlacemark.setStyleSelector(style);

var point = ge.createPoint('');
point.setLatitude(center.getLatitude());
point.setLongitude(center.getLongitude());
pointPlacemark.setGeometry(point);
folder.getFeatures().appendChild(pointPlacemark);

var lookAt = ge.getView().copyAsLookAt(ge.ALTITUDE_RELATIVE_TO_GROUND);
var lat = lookAt.getLatitude();
var lng = lookAt.getLongitude();

// Create a line string placemark
lineStringPlacemark = ge.createPlacemark('');

var style = ge.createStyle('');
var lineStyle = style.getLineStyle();
lineStyle.setWidth(10);
lineStyle.getColor().set('ccff00ff');
lineStringPlacemark.setStyleSelector(style);

var lineString = ge.createLineString('');
lineString.setTessellate(true);

var coords = lineString.getCoordinates();
coords.pushLatLngAlt(north + 0.1, east, 0);
coords.pushLatLngAlt(north + 0.1, west, 0);
coords.pushLatLngAlt(north + 0.35, west, 0);
coords.pushLatLngAlt(north + 0.35, east, 0);
lineStringPlacemark.setGeometry(lineString);
folder.getFeatures().appendChild(lineStringPlacemark);

// Finally, add the folder to the plugin.
ge.getFeatures().appendChild(folder);