Airborne LiDAR Compliance and Quality Assurance Tool

(ComQAT)

ComQAT

Accuracy of Control NetworkControl Density

• Pass/Fail minimum points per square kilometre

• Score density of points per square kilometre (e)e = n / a where, a = project area (km2) n = number of CPs

Survey Area Ground Control Density Requirement

0 - 100km2 ≥5 CPs + minimum 3 GCPs

100 – 400km2 ≥20 CPs + minimum 5 GCPs

≥400km2 20 CPs + 1 CP for every 50km2 over 400km2 + minimum 5 GCPs

Score Point Density 1 - Poor 0 - 0.0022 - Weak 0.002 - 0.005

3 - Average 0.005 - 0.014 - Good 0.01-0.02

5 - Strong ≥0.02

Accuracy of Control NetworkControl Distribution

• spread of points across the project area• how well points cover extremities of project• whether points are weighted to one side of the project

Average distribution

Ideal distribution

Weak distribution

Poor distribution

Absolute Vertical Accuracy

Flatness Rating /

Openness Rating

Flatness: Height difference ground point

to control point (cm)

Openness: % non-ground points within 10m of control point

Poor >8 >50

Weak 6-8 25-50

Average 4-6 15-25

Good 2-4 5-15

Strong <2 <5

Rate ‘flatness’ & ‘openness’ of area around each

control point to determine suitability

Visual Checks