Setting Spatial Projections in AGOL?

[DavidKroeger]

Hi. I am trying to bring layers into AGOL and have them stay in the Virginia State Plane, WKID 2283. I set the basemap for this projection but when I bring in a new layer, it just goes to the standard WGS 1984. This happens even when I start with a layer in 2283, zip it, and then upload it into an AGOL map with a base layer in 2283. 

I know that it's in the World Geoid because I check it from the the layer from the Item page and also in AGOL maps downloaded into ArcGIS Pro. I'm stumped at this point. Thank you for your help. 

[RhettZufelt]

The spatial reference of a web map is determined by the basemap itself.

Create a map in Pro that ONLY uses the Virginia State Plane data (making sure it is defined on the dataset(s)).  Share that as a tiled web layer to AGOL.

Then, in map viewer, add this as the ONLY basemap in the map viewer.  Your entire map will now be in the Virginia State Plane system.

R_

[ChristopherCounsell · Accepted solution]

The Basemap sets the spatial reference. Layers will align to that. If you want to set a different projection, you need to publish a layer with a specific coordinate system. Here is a guide:

https://www.esri.com/arcgis-blog/products/arcgis-online/mapping/changing-the-map-projection-in-arcgi...

The layers will be projected to match the Basemap. This means that it is best to publish layers in the same coordinate system as the intended Basemap.

• Layers published from uploaded files will be projected by ArcGIS online to wgs84.
• Publish from ArcGIS Pro. Layers will be published as the Map properties coordinate system.

Alternatively, publish your layers as wgs84 to align with ESRI Basemaps, and ensure that any later projections back follow the same transformation paths.

[tikola]

This is an important sentence:

"Publish from ArcGIS Pro. Layers will be published as the Map properties coordinate system"

So if you want data in ArcGIS Online to be in certain projection you must be aware which projection your ArcGIS Pro map document is. My hiccup was that I tried to upload single data in certain projection and it always ended up to Web Mercator though the data was locally in another projection. It was the Map Document in ArcGIS Pro that overrided projection in my data.