topic Re: how to find the xmin ymin xmax ymax in ArcGIS JavaScript Maps SDK Questions

how to find the xmin ymin xmax ymax

Sophialim — Mon, 25 Apr 2011 05:45:00 GMT

hi
i am using the
var startExtent = new esri.geometry.Extent(xmin, ymin, xmax, ymax, new esri.SpatialReference({ wkid: 4326 }));
omap.map.setExtent(startExtent);
But how to find the xmin, ymin, xmax and ymax
the spatial reference 4326 need to change?

Re: how to find the xmin ymin xmax ymax

PeterKobylarz — Wed, 04 May 2011 17:42:54 GMT

Can you explain why you are trying to get pre-defined x/y values? Are you trying to get the x/y values of the extent when the map resource loads? Or are you trying to get the coordinates for some other location?

Generally, when you add a layer (ArcGISTiledMapServiceLayer, ArcGISDynamicMapServiceLayer, etc) to your map object, the map's extent object automatically inherits the extent defined in your Map Service Layer. You can get the x/y values from this object by querying the map.extent x/y attributes (http://help.arcgis.com/EN/webapi/javascript/arcgis/help/jsapi_start.htm extent is under the geometry category on the right hand side).

You can also create an extent object and set its x/y values to the extent of another geometry object, such as a polygon.

In general, you shouldn't have to change the spatial reference unless you are dealing with data in mulitple spatial references.

Re: how to find the xmin ymin xmax ymax

MatthewLawton — Wed, 04 May 2011 22:21:32 GMT

You can define the xmin, ymin, xmax, ymax directly if you want to zoom to a specific location different than your default extent. 4326 appears to be the projection id for WGS 84, so I'm assuming it uses decimal degrees for the units. If you wanted to zoom to Los Angeles by default you could declare it like this:

var startExtent = new esri.geometry.Extent(-119.5, 32.5, -116.5, 35.5, new esri.SpatialReference({ wkid: 4326 }));

Re: how to find the xmin ymin xmax ymax

melissaGomez — Tue, 06 Nov 2012 18:57:25 GMT

I see this has been a long time since posted, but I was hoping to see the answer in how to exactly find those coordinates as the example shows for finding Los Angles? I need a refresher on how those coordinates were found. I do not have access to google earth and I know that would be a good source in finding these coordinates. Would anything else help? Please let me know. Thanks.

Re: how to find the xmin ymin xmax ymax

AnthonyGiles — Tue, 06 Nov 2012 19:05:16 GMT

Melissa,

This extent finder application for flex displays a lat/long read out that you can use to gather the coords you need,

http://help.arcgis.com/en/webapps/flexviewer/extenthelper/flexviewer_extenthelper.html

Its a shame that the extent is only shown in web mercator and not geographics

Regards

Anthony

Re: how to find the xmin ymin xmax ymax

melissaGomez — Tue, 06 Nov 2012 19:45:13 GMT

This is perfect!! Thank you so much!!

Re: how to find the xmin ymin xmax ymax

AnthonyGiles — Tue, 06 Nov 2012 22:17:36 GMT

Melissa,

Please do not forget to mark the post as answered by doing the following on the post that best answered your question:

[ATTACH=CONFIG]19078[/ATTACH]

Regards

Anthony

Re: how to find the xmin ymin xmax ymax

JohnGravois — Wed, 07 Nov 2012 14:54:16 GMT

our st. louis regional office put together a sample application for helping streamline the task of identifying extents in both web mercator and wgs84 as well.

Re: how to find the xmin ymin xmax ymax

JimBuehler — Wed, 13 Feb 2013 18:09:30 GMT

Thanks, Anthony! That was excellent!

Equally impressive John!

Re: how to find the xmin ymin xmax ymax

JohnGravois — Wed, 13 Feb 2013 19:13:12 GMT

new map constructor options in version 3.3 of our API have simplified the process of controlling the initial extent of the map.

i put together a simple app to display map center and zoom level to try and make the process even easier.

Re: how to find the xmin ymin xmax ymax

DianaBenedict — Sat, 11 Dec 2021 15:23:51 GMT

Once you have zoomed to your area of interest in Firefox, use the console window in Firebug and type the following:

dojo.toJson(map.extent.toJson());

That is assuming the the esri.map object is called map

Re: how to find the xmin ymin xmax ymax

SteveCole — Wed, 13 Feb 2013 19:46:15 GMT

@Diana-

Thanks for posting that! I've been looking for that reference for the last week and couldn't remember where I had originally read that. You just saved me a whole lot of headache trying to find it again. 😄