topic Re: Reprojection Warning in ArcGIS Maps SDK for Unity Questions

Reprojection Warning

FrancisPolignano — Thu, 31 Aug 2023 13:06:41 GMT

We keep seeing this warning in our Unity app. Is this something to be concerned about?

Source Tiling Scheme's Spatial Reference differs from View Spatial Reference. Reprojection will be required, which may affect performance.

We are using WGS84 (4326) in the Unity app and are consuming these services -

"BasemapUrl": https://ibasemaps-api.arcgis.com/arcgis/rest/services/World_Imagery/MapServer,
"ElevationUrl": https://elevation3d.arcgis.com/arcgis/rest/services/WorldElevation3D/Terrain3D/ImageServer

Re: Reprojection Warning

coryeicher — Thu, 31 Aug 2023 13:17:01 GMT

That warning is telling you that your Unity View is in the WGS84 (4326)
coordinate system (Geographic system), but you are using basemaps that are
in the Spatial Reference: 102100 (3857) coordinate system (Web Mercator
projected system)

The performance impact is that there is reprojection occurring to align the
basemaps with your view. I will let others comment on the severity of this
performance impact.

FWIW, the vast majority of basemaps out-there are in the Web Mercator
projection system. If you have a want/need for your view to be in a non-Web
Mercator coordinate system, and you also want to use a basemap, you can
create your own (not a trivial step). The other way to go is to reproject
your data (from 4326 to 3857), and set up your View to also be in 3857.
Then you'll be in 3857 "across the board" (your data, your basemaps, your
view).

Hope this helps,

-Cory

Re: Reprojection Warning

FrancisPolignano — Thu, 31 Aug 2023 14:09:53 GMT

Thanks for the response, yea mostly interested in best practices and any potential performance impacts. The tutorials seem to set up a map with 4326.

https://developers.arcgis.com/unity/maps/tutorials/display-a-map-ui/