topic Re: how to get map center point? in ArcGIS JavaScript Maps SDK Questions

how to get map center point?

Aaronsi — Wed, 18 Jun 2014 11:16:47 GMT

I use map.extent.getCenter() to get the map center point.But the result is wrong?
I also couldn't find any method of Map Object can get the map center point.
I'm new in Arcgis. I hope someone could help me?
Thanks!

Re: how to get map center point?

LuciHawkins — Wed, 18 Jun 2014 11:40:29 GMT

Hi,

Might need a little more information. You received output but the "result was wrong"? What projection are you using? Did you set the spatialreference for the desired coordinate output?

Thanks,

Luci

Re: how to get map center point?

Aaronsi — Wed, 18 Jun 2014 12:48:04 GMT

Hi,

Might need a little more information. You received output but the "result was wrong"? What projection are you using? Did you set the spatialreference for the desired coordinate output?

Thanks,

Luci

my javascript code are :

var map;

require(["esri/map",], function(Map){

map = new Map("map", {
          basemap: "satellite",
          center: [-46.807, 32.553],
          zoom: 3
        });

});

function getCenterPoint()
{
return map.extent.getCenter();
}

function showCenterPoint()
{
var point = getCenterPoint();

console.log("current map center is x: " + point.x + ", y: " + point.y);
}

the result that I expect is : -46.807, 32.553;
but the real result is : current map center is x: -5376858.37910917, y: 3836121.3860294037
Thanks!

Re: how to get map center point?

KenBuja — Sat, 11 Dec 2021 15:17:20 GMT

The map's projection is in Web Mercator, so the x and y of the center will be returned in meters. You'll want to project this to geographic coordinates, like this

        require([
          "esri/map", "esri/geometry/webMercatorUtils", "dojo/domReady!"
        ], function (
          Map, webMercatorUtils
        ) {
            map = new Map("map", {
                basemap: "satellite",
                center: [-46.807, 32.553],
                zoom: 3
            });

            function getCenterPoint() {
                return map.extent.getCenter();
            }

            map.on("extent-change", function () {
                var point = getCenterPoint();

                var newPoint = webMercatorUtils.webMercatorToGeographic(point);
                console.log("current map center is x: " + newPoint.x + ", y: " + newPoint.y);
            });

        });

Re: how to get map center point?

BenFousek — Sat, 11 Dec 2021 15:17:23 GMT

You can also

map.extent.getCenter().getLatitude();
map.extent.getCenter().getLongitude();

in a web mercator map.

Re: how to get map center point?

Aaronsi — Thu, 19 Jun 2014 01:13:23 GMT

Hi, Kenbuja, Btfou,

After I changed my code like that:

var map;

require(["esri/map", "esri/geometry/webMercatorUtils", "dojo/domReady!"], function(Map, webMercatorUtils){

map = new Map("map", {
          basemap: "satellite",
          center: [-46.807, 32.553],
          zoom: 3
        });

function getCenterPoint()
{
return map.extent.getCenter();
}

map.on("extent-change", function(){

var point = getCenterPoint();

var newPoint = webMercatorUtils.webMercatorToGeographic(point);

console.log("current map center point is x: " + point.getLatitude() + ", y: " + point.getLongitude());
console.log("current map center is x: " + newPoint.x + ", y: " + newPoint.y);
});

});

That worked out perfectly!

Thanks very much!

Re: how to get map center point?

KenBuja — Thu, 19 Jun 2014 11:53:19 GMT

Glad to help.

Please click the check mark in the appropriate post to mark the question as answered. This helps other when searching on solutions to questions like this. For more information, see read the MVP Program page.

Re: how to get map center point?

Aaronsi — Wed, 09 Jul 2014 07:12:42 GMT

Hi, Ken Buja

Good to hear from you! Actually I would like to click the check mark, but the problem is that I couldn't find where the check mark is? Any help?

Re: how to get map center point?

KenBuja — Wed, 09 Jul 2014 12:49:55 GMT

In the new forums, the procedure to mark a question as the answer has been changed. Normally, it should be clear how to mark a question as answered in the new forums. However, this thread was begun in the old forum, and when it was brought over to the new forum, it was classified a discussion and not a question, which means it doesn't have the option to mark it as answered. Hopefully this will be changed soon as they continue to work on the migration process.

Re: how to get map center point?

Aaronsi — Thu, 10 Jul 2014 12:03:28 GMT

Hi Ken Buja Thanks for you reply for me. As you said that means I wasn't able to mark it as answered right now. so I don't need to mark it at the moment, right?