// section of your HTML:
Then in your JavaScript, after initializing your version 2 Google Map (using a
statement like map = new GMap2(document.getElementById('map'));), add the
following two lines of code:
var daylight = new daylightLayer();
daylight.addToMap(map);
obviously, changing map to match your own GMap2 object name as needed. Note
also that this needs to occur before the first call to map.setCenter() in
your code.
You can also add the daylight layer to a single map type (such as Satellite
or Hybrid) if desired by using
daylight.addToMapType(G_SATELLITE_MAP);
instead of the addToMap method. Any valid GMapType should work as a parameter.
The daylightLayer object has the following properties you may find useful:
when
Date/time of the daylight plot. Type: Date. Default: current date/time
opacity
Effectively, the "darkness" of the shadow, where 0 is fully transparent (and
hence invisible) and 1 is fully opaque. Type: Numeric. Default: 0.5 for map
view, 0.8 for satellite/hybrid
active
Whether the daylight layer is displayed when the map is redrawn. Type:
Boolean. Default: true
cityLights
Whether city lights are displayed on the night side. Type: Boolean. Default:
true
*/
var _nTileSize = 256; /* Note: GMaps do not support other tile sizes (as of v2.38, 2 Mar 06) */
var _maxZoom = 20;
var _defaultMapOpacity = 0.8;
var _defaultSatelliteOpacity = 0.8;
var _nightMode = true;
var _pixelsPerLonDegree = new Array();
if (location.hostname == 'dev.daylightmap.com')
var _serverDomain = 'http://dev.daylightmap.com/';
else
var _serverDomain = 'http://www.daylightmap.com/';
var _clientTime = Number(new Date());
var _serverTime = _clientTime;
document.write('');
var _timeCorrection = 0;
function roundTo(number, places)
{
// Rounds the given number to the specifed number of decimal places.
// Note that this is similar to the JS numer.toFixed(), but will accept a negative places parm,
// which some browsers will not for toFixed().
//
// Examples: roundTo(3.1415926535, 4) = 3.1416
// roundTo(314159.26535, -4) = 310000
return Math.round(number * Math.pow(10, places)) / Math.pow(10, places);
};
daylightLayer = function()
{
// daylightLayer object constructor
this.map = null;
// Set default values for major properties
this.when = null;
this.opacity = null;
this.active = true;
this.cityLights = null;
// Internal properties
this.lastZoom = -1;
this.lastRefresh = null;
// These properties are required by GMaps
this.isPng = function() {return true};
this.projection = new GMercatorProjection(_maxZoom);
_timeCorrection = (_serverTime - _clientTime);
// Init the pixel/degree array (this code cribbed from GMercatorProjection)
var b = _nTileSize;
for (var i = 0; i < _maxZoom; i++)
{
_pixelsPerLonDegree.push((b / 360).toFixed(10));
b *= 2;
}
};
daylightLayer.prototype = new GTileLayer(new GCopyrightCollection(''), 0, _maxZoom);
daylightLayer.prototype.setMap = function()
{
try {
if (!this.map)
this.map = map; // try for a commonly-named global var
} catch (e) {}
return this.map;
};
daylightLayer.prototype.getCopyright = function(bounds, zoom)
{
var opacity = _defaultMapOpacity;
for (var i = 0; i < this.map.getMapTypes().length; i++)
if (this.map.getMapTypes()[i].opacity)
{
opacity = this.map.getMapTypes()[i].opacity;
break;
}
if ((this.map.getCurrentMapType() == G_SATELLITE_MAP) ||
(this.map.getCurrentMapType() == G_HYBRID_MAP) ||
(opacity > 0.5))
var copyright = 'DaylightMap';
else
var copyright = 'DaylightMap';
// return copyright; //GMap v2.44-
return {prefix: '', copyrightTexts:[copyright]};//GMap v2.45+
};
daylightLayer.prototype.getOpacity = function()
{
if (this.opacity != null)
// Opacity as been overridden to a specific value
result = parseFloat(this.opacity);
else
{
// Otherwise, default opacity is adaptive
if (this.setMap())
{
if ((this.map.getCurrentMapType() == G_SATELLITE_MAP) ||
(this.map.getCurrentMapType() == G_HYBRID_MAP))
result = _defaultSatelliteOpacity;
else
result = _defaultMapOpacity;
}
else
{
if (this.getCityLights())
result = _defaultSatelliteOpacity;
else
result = (_defaultSatelliteOpacity + _defaultMapOpacity) / 2;
}
}
return result.toPrecision(2); // there's no need for any greater precision than this
};
daylightLayer.prototype.getCityLights = function(mapType)
{
if (this.cityLights == false)
// City lights have been specifically turned off
return false;
else if (this.cityLights == true)
// City lights have been specifically turned on
return true;
else
{
// Default cases
if (!this.setMap())
return true;
if (!mapType)
mapType = this.map.getCurrentMapType();
if (_nightMode)
return true;
else if (mapType == G_NORMAL_MAP)
// City lights default to off for map view
return false;
else
// City lights default to on for satellite-based views
return true;
}
};
daylightLayer.prototype.addToMap = function(newMap)
{
// Add the daylight layer to the supplied GMap2 object
this.map = newMap;
mapType = this.map.getCurrentMapType();
// if (mapType == NOC){
//map.setMapType(G_SATELLITE_TYPE);
var types = this.map.getMapTypes();
//for (var i = 0; i < types.length; i++)
//this.addToMapType("NOC");
this.addToMapType(types[4]); // typ NOC
//this.addToMapType(G_SATELLITE_TYPE);
//}
};
daylightLayer.prototype.addToMapType = function(mapType)
{
// Add the daylight layer to a single map type (like G_SATELLITE_MAP)
mapType.getTileLayers().splice(1, 0, this);
if (this.getCityLights(mapType))
mapType.getMaximumResolution = function(){return 8;};
};
daylightLayer.prototype.refresh = function()
{
// Refresh the daylight layer
// This Zoom kludge refreshes all map tiles
if (this.setMap())
{
this.lastZoom = -1;
this.map.setZoom(this.map.getZoom());
}
};
daylightLayer.prototype.getTileUrl = function(point, zoom)
{
// Interface to the tile server
// tile_n_2_0_0_1178264700.png
// night_4_1_8.png
if (!this.active)
return '';
if (_nightMode)
var tileName = 'tiles/night_png/night_';
else
{
var tileName = 'tiles/cache/tile_';
if (this.getCityLights())
tileName += 'n_';
}
tileName += zoom + '_' + point.x + '_' + point.y;
if (!_nightMode)
{
// Establish the date/time to send
if (this.when != null)
var timestamp = this.when;
else
{
if (zoom != this.lastZoom)
{
if (_timeCorrection == 0)
_timeCorrection = (_serverTime - _clientTime);
// Using current date/time - Round it to the nearest minute and correct to server time
this.lastRefresh = new Date(60000 * ((Number(new Date()) + _timeCorrection) / 60000).toFixed(0));
this.lastZoom = zoom;
}
var timestamp = this.lastRefresh;
}
// Use some rounding based on zoom level to improve caching of tiles
timestamp = roundTo(Number(timestamp) / 1000, Math.min(0, zoom - 3));
tileName += '_' + timestamp;
}
tileName = _serverDomain + tileName + '.png';
//try { console.log(tileName); } catch(e) {};
//GLog.write(tileName);
return tileName;
};
//]]>