Change CRS in ArcGIS online

[AgencyDeveloper]

We are using ArcGIS online to create and store layers. Once layers are created we download them from ArcGIS online using REST apis and insert data into our tables. The CRS is EPSG:3857, is it possible to change it in ArcGIS to CP4326?

Thanks

[Egge-Jan_Pollé]

Hi Agency Developer‌,

Can you please indicate how you create your layers? Do you set a targetSR? 

If you don't specify the targetSR data will be automatically transformed to wkid 102100 (-> wkid 3857 -> Web Mercator) when published to ArcGIS Online.

Egge-Jan

[Anonymous User]

All layers created and stored in ArcGIS Online will be kept in Web Mercator Auxiliary Sphere (EPSG:3857). You can change this in ArcMap or ArcGIS Pro if you use the "Define Projection" tool to put it in whatever coordinate system you prefer, but you cannot change it in ArcGIS Online. 

[Egge-Jan_Pollé]

Hi Alexandra Scott‌,

You cannot change a Spatial Reference in ArcGIS Online once set, but you can define another (non-3857) Spatial Reference when you create your layer, right?

Much of our content is in RD_New (EPSG:28992):

    "spatialReference" : {       "wkid" : 28992,        "latestWkid" : 28992     }

Cheers,

Egge-Jan

[Anonymous User]

Hi Egge-Jan Pollé‌

Yes, you can define whatever spatial reference you'd like depending on how you're creating the layers, but anything hosted and stored in ArcGIS Online is automatically put in Web Mercator regardless of how it's defined otherwise. For example: publishing a layer from ArcGIS Pro that's in EPSG:28992 to ArcGIS Online will be converted to Web Mercator while it's in ArcGIS Online. The source data stays in the spatial reference you defined, but while viewed in and downloaded from ArcGIS Online, it will be in Web Mercator. 

[Egge-Jan_Pollé]

Hi Alexandra Scott‌,

I tend not to agree with you, or am I missing something? My data in ArcGIS Online is in RD_New (not Web Mercator)  and when I download it to open it in ArcGIS Desktop it is still in RD_New...

See for example this screen dump below

Egge-Jan

[KhaledHassen]

Data stored in online feature service will be defaulted to 102100 projection if it is not defined with the source and publishing parameter.

If you publish SD file with a specific projection and transformation parameters, online feature service will preserve the spatial reference of the map defined within the SD file. We will not default the online feature service to 102100 in this case.

Publishing any other data source (shapefile, filegdb, excel, etc.), we will default to mercator (102100 or latest=3857), unless you pass a tergetSR publishing params.

Pl. note the feature service and data stored in online FS will always have the same SR.

And Yes once you have your service in a specific SR, you cannot change it once publish.

Khaled Hassen

Online Feature Service Dev Lead