LE90: Understanding Linear Error at 90% Confidence

LE90 (Linear Error at 90%) is a widely used measure of horizontal positional accuracy in GIS, surveying, remote sensing, photogrammetry, and digital mapping. It defines the horizontal error threshold within which 90% of tested positions are expected to fall. LE90 is useful for evaluating the accuracy and reliability of geospatial datasets such as orthophotos, satellite imagery, drone maps, LiDAR data, topographic maps, and GIS feature layers.

A lower LE90 value generally indicates higher positional accuracy, making it an important metric for quality control and data validation. GIS professionals use LE90 to compare mapping products, assess survey results, verify spatial datasets, and determine compliance with project accuracy specifications. It is particularly valuable in UAV mapping, aerial surveying, cadastral mapping, infrastructure development, and remote sensing projects, where precise horizontal positioning is critical. By understanding LE90, organizations can better evaluate geospatial data quality and select datasets suitable for accurate GIS analysis and decision-making.