AutoTURN Online: What is the accuracy level when using the aerial image or Google Maps option as the background for the analysis?

The accuracy level of simulating on an aerial image or Google Maps is predominantly dependent on the scaling of the background.

For an aerial image, users have the control to adjust the scale by making a reference to a known measurement on the image (Note: this is part of the import image workflow).
For using Google Maps as the background, users do not have control over adjusting the scale as this is done by Google.

Since aerial imagery can differ from location-to-location and in the worst case be distorted, we recommend users to double check key dimensions using our Measure Distance tool Measure_Distance_Tool.jpg.
Lastly, performing swept path analysis on aerial images and Google Maps is intended as a quick preliminary/conceptual analysis.

For detailed analysis, it is still best to analyze on CAD geometry like importing DXF files as the background.