topic How to use the latitude and longitude to get local time, not the server time? in ArcGIS JavaScript Maps SDK Questions

How to use the latitude and longitude to get local time, not the server time?

HsuKao-Ming — Tue, 21 Aug 2018 15:01:30 GMT

hey guyts,

How to use the latitude and longitude to get local time, not the server time?

because I can't find how to use the latitude and longitude to get local time,

The original method is to use the timezone through google to get the offset for daylight-savings time.

I want to solve this problem.

Re: How to use the latitude and longitude to get local time, not the server time?

SteveCole — Tue, 21 Aug 2018 15:38:11 GMT

ESRI does have a World Time Zone layer in the Living Atlas. Query your lat/long point against that service to find out what the time offset is to get your local time.

Re: How to use the latitude and longitude to get local time, not the server time?

HsuKao-Ming — Wed, 22 Aug 2018 02:12:18 GMT

Steve,

How can I use that for javascript or json?

Re: How to use the latitude and longitude to get local time, not the server time?

SteveCole — Sun, 12 Dec 2021 05:21:08 GMT

You would use Query & QueryTask similar to what's shown in this example. The example uses the location where you click on the map but in your case, you would create a point using your lat/long values and then pass that as the value used with query.Geometry.

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"/>
    <title>Simple Map</title>
    <link rel="stylesheet" href="https://js.arcgis.com/3.25/esri/css/esri.css">
    <style>
      html, body, #map {
        height: 100%;
        margin: 0;
        padding: 0;
      }
    </style>
    <script src="https://js.arcgis.com/3.25/"></script>
    <script>
      var map;

      require(["dojo/on","esri/map","esri/layers/FeatureLayer","esri/tasks/query", "esri/tasks/QueryTask","dojo/domReady!"], function(on,Map,FeatureLayer,Query,QueryTask) {
        map = new Map("map", {
          basemap: "topo",  //For full list of pre-defined basemaps, navigate to http://arcg.is/1JVo6Wd
          center: [-100.45, 37.75], // longitude, latitude
          zoom: 4
        });
        var featureLayer = new FeatureLayer("https://services.arcgis.com/P3ePLMYs2RVChkJx/ArcGIS/rest/services/World_Time_Zones/FeatureServer/0",{opacity:0.5});

        map.addLayer(featureLayer);
        
        map.on("click", function(evt){
            var queryTask = new QueryTask("https://services.arcgis.com/P3ePLMYs2RVChkJx/ArcGIS/rest/services/World_Time_Zones/FeatureServer/0");
            var query = new Query();
            query.geometry = evt.mapPoint;
            query.outFields = ["*"];
            queryTask.on("complete", processResults);
            queryTask.execute(query);
            
            function processResults(results) {
              var features = results.featureSet.features;
              if (features.length > 0) {
                alert('The zone offset for the clicked location is ' + features[0].attributes.ZONE);
              };              
            };
        });
        
      });
    </script>
  </head>

  <body>
    <div><h2>Click on the map to get the time zone offset</h2></div>
    <div id="map"></div>
  </body>
</html>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How to use the latitude and longitude to get local time, not the server time?

SteveCole — Sun, 12 Dec 2021 05:21:10 GMT

I tried to update my sample to actually return the local time at the location clicked but I'm having trouble doing so. It's returning the time but off one hour so I don't know if that's due to daylight savings or GMT being 0, etc. Perhaps a more savvy coder can find the error of my ways.

Here's an updated processResults function that returns the timezone offset and the local time (but off by one hour):

            function processResults(results) {
              var features = results.featureSet.features;
              if (features.length > 0) {
                var timeOffset = features[0].attributes.ZONE;
                var curDate = new Date();
                curDate.setUTCMinutes(curDate.getUTCMinutes() + (timeOffset*60));
                
                var hours = curDate.getUTCHours();
                var minutes = curDate.getUTCMinutes();
                var ampm = hours >= 12 ? 'pm' : 'am';
                hours = hours % 12;
                hours = hours ? hours : 12; // the hour '0' should be '12'
                minutes = minutes < 10 ? '0'+minutes : minutes;
                var strTime = hours + ':' + minutes + ' ' + ampm;
  
                alert('The zone offset for the clicked location is ' + features[0].attributes.ZONE + '\n and the local time is ' + strTime); //curDate.toUTCString());
              };              
            };‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍