Module 1.1 Lab: Calculating Metrics for Spatial Data Quality

The horizontal precision of 68% was 4.5 m.

The distance between the average waypoint location and reference point was 3.2 m; horizontal accuracy.

 

The estimated horizontal accuracy was 3.2 m, based on the distance between the average waypoint location and the reference point. The 68% horizontal precision was 4.5 m. Therefore, the horizontal accuracy error was 1.3 m smaller than the 68% precision estimate. The average GPS position was closer to the reference location than the distance representing the spread of 68% of the repeated observations. Based on these results, the difference between horizontal accuracy and precision does not appear substantial.

 

Vertical Accuracy at 68% was 5.96 m.

The vertical precision is 5.9 m.

The difference between these two values is only approximately 0.07 m, indicating that vertical accuracy error and vertical precision are very similar.

Overall, the results do not provide strong evidence of significant horizontal bias because the 3.2 m displacement of the average waypoint from the reference point is smaller than the 4.5 m horizontal precision estimate.

Vertically, the average GPS elevation was 5.96 m higher than the reference elevation, which indicates a positive vertical offset. However, because the 68% vertical precision was also approximately 5.9 m, the magnitude of this offset is similar to the variability observed among the elevation measurements. Therefore, the results should be interpreted cautiously rather than as evidence of a strong systematic bias.