CE90: Circular Error 90% in GIS and Geospatial Accuracy

CE90 (Circular Error 90%) is a key geospatial accuracy measurement used in GIS, remote sensing, surveying, photogrammetry, drone mapping, and satellite imagery. It defines the radius of a circle centered on the true geographic position that contains approximately 90% of the horizontal positional errors in a dataset. CE90 helps GIS professionals determine how accurately features, coordinates, and mapped locations represent their real-world positions.

A smaller CE90 value indicates higher horizontal accuracy. For example, a CE90 of 1 meter means that 90% of the measured positions are expected to be located within 1 meter of their true horizontal position. This metric is commonly applied when assessing orthophotos, digital elevation products, GIS databases, UAV imagery, GNSS surveys, and geospatial mapping products. CE90 provides a practical way to compare datasets and verify whether their positional accuracy meets specific mapping, engineering, or surveying requirements.