I’m sure there’s a better way to convert a sketch layer into coordinates, but this worked for me.
Use Geoprocessing tool: Layer to KML
Then use KML to Layer to import it back in with the coordinate system the map is in.
Open the features table, calculate:
New field: Lon
Lon = shapeToY(!Shape!)
def function(shape): point=shape.getPart(0) return point.Y
Repeat for the calculation for x