WMTS and Georeferenced Rasters Incompatible With Each Other

Question

My goal is to host a project online containing several basemaps of historical aerial imagery/orthophotography

I have georeferenced several aerial photos on ArcGIS Pro with the following spatial reference and uploaded them to ArcGIS Online:
Geographic Coordinate System WGS 1984
WKID 4326
Authority EPSG
Angular Unit Degree (0.0174532925199433)
Prime Meridian Greenwich (0.0)
Datum D WGS 1984
Spheroid WGS 1984
Semimajor Axis 6378137.0
Semiminor Axis 6356752.314245179
Inverse Flattening 298.257223563

I also added WMTS database connections for three servers hosted by the City of Toronto. On ArcGIS Pro, these WMTS connections have the same spatial reference as above, but ArcGIS Online is providing me with the error that the WMTS layers are "Incompatible with current basemap". Inversely, if I set a WMTS layer as the main basemap, my georeferenced rasters become incompatible.

I cannot figure out for the life of me what else may be causing the WMTS layers to be incompatible, if not their coordinate system...

tikola · Answer

No as WMTS offers the data in certain projections and you are limited to ones service provides. So there is no way to reproject service to another projection in ArcGIS Online on the fly. Local data yes but not OGC services.

So bascially you must use basemap that matches the projections that WMTS provides. Or another approach is update WMTS service provide data in new projections needed.

Also if you turn your georeferenced rasters from local tiled service to imagery service it starts to reproject those in WMTS projection. So ArcGIS Online makes reprojection on the fly for local data but depending on data it may have some limitations. Pre calculated tiles is one of those limitations.

In generally - try to use always a basemap that suits well to your data (same projection) and your system performs in optimal way. On the fly reprojection works with some limitations but it never improves the performance. Then the amount you lose depends on your data and if amount of data is minor then loss or performance might also be minor but always there is some.

EmiliaKolodko · Answer

Hey y'all! Turns out in the WKID metadata the WMTS layer (on ArcGIS Pro) had originally been another geographic coordinate system, I just didn't realize I had ever changed it. Now my question is: is it possible to change the coordinate system of the WMTS on ArcGIS online to match my georeferenced rasters? (in this example, it would be to change from 102100 (3857) to 4326)