topic Re: No Coordinates in ArcGIS JavaScript Maps SDK Questions

No Coordinates

AhmadLibda — Fri, 14 Jul 2017 08:09:28 GMT

I learned that The spatial reference for a map is defined either by the extent passed to the map constructor or by the first layer added to the map.

coordinate system - Set custom spatial reference to base map in arcgis javascript api - Geographic Information Systems S…

I am new to GIS. So this is my code:

   var govs= new TileLayer({
        url: "http://localhost:6080/arcgis/rest/services/services/MapServer",
        visible: false
    });
    var map = new Map({ });
var view = new MapView({
        container: "viewDiv", // Reference to the scene div created in step 5
        map: map, // Reference to the map object created before the scene
        zoom: 1, // Sets zoom level based on level of detail (LOD)
        center: [86999,99999] // Sets center point of view using longitude,latitude
    });
    map.layers.add(govs);

I get a "Null" for both mapPoint.latitude and longitude when i print them in a popup using the code:

view.on("click", function (event) {
        event.stopPropagation(); // overwrite default click-for-popup behavior
        // Get the coordinates of the click on the view
        var lat = Math.round(event.mapPoint.latitude *1000 )/1000 ;
        var lon = Math.round(event.mapPoint.longitude * 1000) / 1000;
        view.popup.open({
            // Set the popup's title to the coordinates of the location
            title: "Reverse geocode: [" + lon + ", " + lat + "]",
            location: event.mapPoint // Set the location of the popup to the clicked location
        });
        view.popup.content = "Hello,, ";
    });

Also, altering "center" in view constructor doesn't seem to affect the starting center point of the map. However, "zoom" works.

I also tried to define "spatial reference" within the view (but no use):

var view = new MapView({
        container: "viewDiv", // Reference to the scene div created in step 5
        map: map, // Reference to the map object created before the scene
        zoom: 1, // Sets zoom level based on level of detail (LOD)
        center: [86999,99999] , // Sets center point of view using longitude,latitude
extent: { // autocasts as new Extent()
            xmin: 75639.85130000021,
            ymin: 70262.05010000058,
            xmax: 108900.84379999992,
            ymax: 111618.54690000042,
            spatialReference: 28191
        }
   });

Re: No Coordinates

RobertScheitlin__GISP — Fri, 14 Jul 2017 13:17:30 GMT

Ahmad,

Also, altering "center" in view constructor doesn't seem to affect the starting center point of the map

Center: If set in the constructor, this property will be ignored if the viewpoint or extent properties are also set in the constructor.

Because you are setting the extent the center is ignored.

The mapPoint latitude and longitude will be null for a local coordinate system like you are using if you want the mapPoint coordinates you need to use x and y.

Re: No Coordinates

AhmadLibda — Fri, 14 Jul 2017 16:20:55 GMT

I omitted the extent part, still changing the center is not doing anything

Re: No Coordinates

RobertScheitlin__GISP — Fri, 14 Jul 2017 16:23:24 GMT

Have you tried using an actual lat lon cordinates and not your local XY value?

Re: No Coordinates

AhmadLibda — Fri, 14 Jul 2017 16:43:27 GMT

I do not know what you mean by "actual lat lon coordinates" but I tried a wide range of values, and I am always at the same starting point which is the center of my layers.

Re: No Coordinates

RobertScheitlin__GISP — Fri, 14 Jul 2017 16:57:13 GMT

I mean

center: [34.336, 31.49]

These are the WGS 84 lat lon values for

center: [86999,99999]

Re: No Coordinates

AhmadLibda — Fri, 14 Jul 2017 18:14:58 GMT

no use

Re: No Coordinates

HemingZhu — Fri, 14 Jul 2017 18:48:40 GMT

You first statement is collect. so if you put your TileLayer in Map constructor, then you will have your mapview's spatialreference same as you tilelayer:

var gov= new TileLayer({
        url: "http://localhost:6080/arcgis/rest/services/services/MapServer",
        visible: false
    });
    var map = new Map({

layers:[gov]

});

Zoom and center is only work when your use esri basemap (102100). Extent will work when you don't use esri basemap.

similarly event.mapPoint.latitude is only work when you mapview spatial reference is 102100 or 3857. but you can always use event.mapPoint.x to get the cordinates in map unit that you are using.

Re: No Coordinates

RobertScheitlin__GISP — Sun, 12 Dec 2021 03:37:09 GMT

Ahmad,

This works fine for me:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="initial-scale=1,maximum-scale=1,user-scalable=no">
  <title>Get started with MapView - Create a 2D map - 4.4</title>
  <style>
    html,
    body,
    #viewDiv {
      padding: 0;
      margin: 0;
      height: 100%;
      width: 100%;
    }
  </style>

  <link rel="stylesheet" href="http://js.arcgis.com/4.4/esri/css/main.css">
  <script src="http://js.arcgis.com/4.4/"></script>

  <script>
    require([
      "esri/Map",
      "esri/views/MapView",
      "esri/layers/TileLayer",
      "esri/geometry/Point",
      "dojo/domReady!"
    ], function(Map, MapView, TileLayer, Point) {

      var layer = new TileLayer({
        url: "http://localhost:6080/arcgis/rest/services/services/MapServer"
      });

      var map = new Map({});

      var pt = new Point({
        x: 86999,
        y: 99999,
        spatialReference: 28191
      });

      var view = new MapView({
        container: "viewDiv",
        map: map,
        zoom: 1,
        center: pt
      });
      map.layers.add(layer);

      view.on("click", function (event) {
        event.stopPropagation(); // overwrite default click-for-popup behavior
        // Get the coordinates of the click on the view
        var lat = Math.round(event.mapPoint.y *1000 )/1000 ;
        var lon = Math.round(event.mapPoint.x * 1000) / 1000;
        view.popup.open({
            // Set the popup's title to the coordinates of the location
            title: "Reverse geocode: [" + lon + ", " + lat + "]",
            location: event.mapPoint // Set the location of the popup to the clicked location
        });
        view.popup.content = view.spatialReference.wkid.toString();
    });

    });
  </script>
</head>

<body>
  <div id="viewDiv"></div>
</body>
</html>
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Re: No Coordinates

AhmadLibda — Sat, 15 Jul 2017 05:10:08 GMT

Robert,

This works fine for me too

Thanks alot.

Re: No Coordinates

RobertScheitlin__GISP — Sat, 15 Jul 2017 12:04:57 GMT

Ahmad, great don't forget to mark this question as answered then.