Files
openlayers/examples/kml-timezones.js
2013-06-27 10:17:40 -06:00

88 lines
2.1 KiB
JavaScript

goog.require('ol.Expression');
goog.require('ol.Map');
goog.require('ol.RendererHint');
goog.require('ol.View2D');
goog.require('ol.layer.TileLayer');
goog.require('ol.layer.Vector');
goog.require('ol.parser.KML');
goog.require('ol.proj');
goog.require('ol.source.Stamen');
goog.require('ol.source.Vector');
goog.require('ol.style.Polygon');
goog.require('ol.style.Rule');
goog.require('ol.style.Style');
// calculate opacity based on difference from local noon
function getOpacity(feature) {
var opacity = 0;
var name = feature.get('name'); // e.g. GMT -08:30
var match = name.match(/([-+]\d{2}):(\d{2})$/);
if (match) {
var hours = parseInt(match[1], 10);
var minutes = parseInt(match[2], 10);
var date = new Date();
var diff = 60 * hours + minutes + date.getTimezoneOffset();
var remote = new Date(date.getTime() + diff * 60000);
// offset from local noon (in hours)
var offset = Math.abs(12 - remote.getHours() + (remote.getMinutes() / 60));
if (offset > 12) {
offset = 24 - offset;
}
opacity = 1 - offset / 12;
}
return opacity;
}
var style = new ol.style.Style({rules: [
new ol.style.Rule({
symbolizers: [
new ol.style.Polygon({
fillColor: '#ffff33',
strokeColor: '#ffffff',
opacity: new ol.Expression('getOpacity(this)')
})
]
})
]});
var vector = new ol.layer.Vector({
source: new ol.source.Vector({
projection: ol.proj.get('EPSG:4326')
}),
style: style
});
var raster = new ol.layer.TileLayer({
source: new ol.source.Stamen({
layer: 'toner'
})
});
var map = new ol.Map({
layers: [raster, vector],
renderer: ol.RendererHint.CANVAS,
target: 'map',
view: new ol.View2D({
center: [0, 0],
zoom: 2
})
});
var kml = new ol.parser.KML({dimension: 2});
var url = 'data/kml/timezones.kml';
var xhr = new XMLHttpRequest();
xhr.open('GET', url, true);
/**
* onload handler for the XHR request.
*/
xhr.onload = function() {
if (xhr.status == 200) {
var projection = map.getView().getProjection();
vector.parseFeatures(xhr.responseText, kml, projection);
}
};
xhr.send();