What is the spatial ref of an AGOL web map extent?

Question

Hi,

I have created a web map and the spatial reference in the web map data when I request the specific item is (presumably based on the base layer spatial reference?):

"spatialReference": {
        "wkid": 102100,
        "latestWkid": 3857
    }

but the extent in the web map content item is:

"extent": [[105.533276992,
        -43.6430919145],
        [159.105442464,
        -9.23004701800001]]

What is the spatial reference of the extent? Is it EPSG:4326 and if so is this always the case for web maps? I could not find a definitive reference for this.

Cheers,
Chris Mugdan

ChristopherMugdan · Answer

The "extent" I am referring to here is the one that is in the response to a request of the form: https:///sharing/rest/content/users/?num=10&f=json&token= and the extent information appears to be in decimal degrees for the web map I have created. I want to know what CRS that extent is in. Below is a snippet of the response. Also, do you know the answer to my question about how to find what units the web map is in? Cheers, Chris ....... "type": "Web Map", "typeKeywords": ["ArcGIS Online", "Explorer Web Map", "Map", "Online Map", "Web Map"], "description": null, "tags": ["Australia test"], "snippet": "Australia test map", "thumbnail": "thumbnail/_7B13F314F4-7C86-4F95-B767-FE0871E20C3F_7D.png", "documentation": null, "extent": [[100.922048628469, -45.0493616849178], [163.716670827299, -7.28393079517143]], "categories": [], "spatialReference": null, "accessInformation": null, "licenseInfo": null, "culture": "english (united states)", .......

Anonymous User · Answer

I think I am confused by what you mean when you say "extent CRS is in the content response json". I have to be honest and say I do not know wha that means.

For a hosted service you can see the information about extent and spatial reference in the rest endpoint:

https://services.arcgis.com/Wl7Y1m92PbjtJs5n/arcgis/rest/services/Domain_calc2/FeatureServer?token=EkFxzzyYYSFBLjfDyJiWp…

You can find the URL for the rest endpoint on the item details page. It is on the bottom right of the page in a section called URL.

ChristopherMugdan · Answer

Also, how do I find what units the web map is in? If the web map is in EPSG:3857 it will be metres I presume, but is there a way of getting that information as one can do when interrogating a map service in ArcGIS Server? I have not found it in the web map item (from content) nor the web map data (from the web map data request.)

Cheers,

Chris