Esri Leaflet

Query without a map

It is not necessary to add a layer to a map in order to execute a spatial query. More information about Queries can be found in the L.esri.Query documentation.

computing...
<html>
<head>
  <meta charset="utf-8" />
  <title>Query without a map</title>
  <meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no" />

  <!-- Load Leaflet from CDN -->
  <link rel="stylesheet" href="https://unpkg.com/leaflet@1.5.1/dist/leaflet.css"
  integrity="sha512-xwE/Az9zrjBIphAcBb3F6JVqxf46+CDLwfLMHloNu6KEQCAWi6HcDUbeOfBIptF7tcCzusKFjFw2yuvEpDL9wQ=="
  crossorigin=""/>
  <script src="https://unpkg.com/leaflet@1.5.1/dist/leaflet.js"
  integrity="sha512-GffPMF3RvMeYyc1LWMHtK8EbPv0iNZ8/oTtHPx9/cc2ILxQ+u905qIwdpULaqDkyBKgOaB57QTMg7ztg8Jm2Og=="
  crossorigin=""></script>


  <!-- Load Esri Leaflet from CDN -->
  <script src="https://unpkg.com/esri-leaflet@2.3.0/dist/esri-leaflet.js"
  integrity="sha512-1tScwpjXwwnm6tTva0l0/ZgM3rYNbdyMj5q6RSQMbNX6EUMhYDE3pMRGZaT41zHEvLoWEK7qFEJmZDOoDMU7/Q=="
  crossorigin=""></script>


  <style>
    body { margin:0; padding:0; }
    #map { position: absolute; top:0; bottom:0; right:0; left:0; }
  </style>
</head>
<body>

<style>
  #message {
    margin: 10px
  }
</style>

<div id="map">
  <div id="message">computing...</div>
</div>
<div id="invisibleMap"></div>

<script>
  // html5 geolocation requires a secure connection
  if (window.location.host === 'esri.github.io' && window.location.protocol !== 'https:') {
    window.location.protocol = 'https';
  }

  document.getElementById('map').style.height = '100px';

  var message = document.getElementById('message');

  // its not necessary to instaniate a map in order to execute a spatial query,
  //  we do it here because it provides a convenient way to ask the user for their HTML5 location
  var map = L.map('invisibleMap');
  map.locate();

  map.on('locationfound', function (e) {
    // use location to find out which census block they are inside
    L.esri.query({
      url: 'https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/1'
    }).intersects(e.latlng).run(function (error, censusBlocks) {
      if (error) {
        message.innerHTML =
          'there may have been an error querying your location';

        return;
      }

      if (censusBlocks.features.length > 0) {
      // if we find a match dig into the feature attributes to retrive median age
        message.innerHTML =
          'the median age of the census block where you are currently located is <b>' + censusBlocks.features[0].properties.MED_AGE +
          '</b> years old';
      } else {
      // otherwise, fail gracefully
        message.innerHTML =
          'either you aren\'t currently in the United States or you prefer not to say';
      }
    });
  });
</script>

</body>
</html>