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Mobile Mapping Validation
Allen Nobles, PLSNobles Consulting GroupTallahassee, Florida
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
David J. WardBusiness Development DirectorTerrapoint USA
Test Project
Evaluate the TITAN mobile scanning system against:
•Conventional survey techniques
•Static Scanning
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
TITAN mobile Lidar system• 360 degree coverage• 100 meter effective range• Highway speed collection• Georeferenced video• 4 meter collection height• Vehicle contained operation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Four Riegl LMS - Q120 lasers
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
TITAN Elevator is operated from inside the vehicle
TITAN in Production
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Lidar and Linescan Fusion
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Project Parameters
8500 foot suburban 4 lane highway
GPS base station adjacent to site
Collection time 1.3 hours
Two passes each direction
400 points per square meter
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Project SiteTallahassee, Florida
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Gaines Street, Tallahassee, Florida
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Titan Lidar Processing
GPS IMU solution provides the trajectory
Linked with scan angles and ranges
Results is calibrated point cloud
Each point has X,Y,Z and Intensity
Passes are checked against one another
with Terrascan
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
TitanQC Process
Collected independent survey data• Kinematic profile
Terrascan• Horizontal alignment check• Vertical alignment check
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Titan Survey Check
Data
Kinematic profile of project site Average DZ -0.049 FeetMinimum DZ -0.243Maximum DZ +0.112Average Magnitude 0.062Root Mean Square 0.079 (1 sigma)Std deviation 0.059
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Intensity Image to Check Alignment of Striping
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Vertical Check Between Drivelines
Match to 1-2 cm
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
We chose to test the system on a real project.
The test project was a completed and approved survey for FDOT using their standard survey practices.
A full DTM was provided to FDOT and check cross-sections were used to check the DTM data (QA/QC).
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
The project area was later scanned with a HDS scanner.
Gaines Street, Tallahassee, Florida
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Gaines Street, Tallahassee, Florida
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Gaines Street, Tallahassee, Florida
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
How do you test a mobile scanner?
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
How good was the survey control?
Is survey point data absolute?
How do you test a mobile scanner?
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Typical survey control results for these projects run from 1:40,000 to 1:60,000.
Survey data is also adjusted over the total site to remove errors.
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Lowest Flight Altitude 360 feetNegative Scale 1”=60’Spot Elevation Accuracy +/- 0.05’
The project area was also surveyed using LAMP (Low Altitude Mapping Photography)
Control SurveyLamp Data Checks
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Elevation DataPoint Survey LAMP Difference301 87.97 87.994 +0.024302 87.13 87.162 +0.032303 86.77 86.793 +0.023304 87.30 87.334 +0.034305 86.17 86.191 +0.021306 87.77 87.778 +0.008308 86.45 86.499 +0.049309 86.93 86.665 -0.010310 86.28 86.312 +0.024311 86.84 88.863 +0.023
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Who is checking who now?
How do you test a mobile scanner?
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
How good was the survey control? Survey points are not absolute. Do you check just control points? Do you test against the DTM? Surfaces are not flat in the scanner data. Adjusted survey control vs. single point RTK Local vs. network How do you check 3D data?
Project was scanned using a Leica ScanStation.
Each setup was adjusted into the existing ground control.
Two Traverses (total length 7,177 feet)Avg. Hor. error = 0.08 feet (1:40,000)Avg. Vertical error = 0.10 feet
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Cross-section Points
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Results from cross-data from ground survey vs. scanner data (search radius of 0.25 feet and a
max. elevation tolerance of 0.10 feet).
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Used 143 points at cross-section areas. 75 points supported (68 unsupported) 53 points meet rejection tolerance 22 points were rejectedMean Deviations = 0.052 feetRMS Deviation = 0.065 feet
Results from the survey DTM vs. the HDS scanner data (search radius of 0.25 feet and a
max. elevation tolerance of 0.10 feet).
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Used 368 points at cross-section areas. 159 points supported (209 unsupported) 92 points meet rejection tolerance 67 points were rejectedMean Deviations = 0.060 feetRMS Deviation = 0.070 feet
Checkpoint results using only shots within the pavement (search radius of 1.0 feet).
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Used 52 points at cross-section areas. 50 points supported (2 unsupported)37 points meet rejection tolerance13 points were rejectedMean Deviations = 0.047 feetRMS Deviation = 0.060 feet
Checkpoint results using only shots within the pavement (search radius of 0.25 feet).
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
Used 52 points at cross-section areas. 52 points supported (0 unsupported) 35 points met rejection tolerance17 points were rejectedMean Deviations = 0.044 feetRMS Deviation = 0.055 feet
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation
HDS Scans Titan Scans
2009 Spar Conference 2009 Spar Conference Denver, ColoradoDenver, Colorado
Mobile Mapping ValidationMobile Mapping ValidationTitan – HDS Comparison
Checkpoints for Horizontal Comparison
Titan – HDSCheckpoints for Horizontal Comparison
ΔN-0.0223
0.0379
0.0167
-0.1168
0.0029
0.0134
0.0137
0.1216
-0.0168
0.0643
0.1452
-0.0435
-0.0259
-0.1587
ΔE-0.0023
0.0508
-0.0263
0.2692
0.0849
-0.0286
0.0902
0.1068
0.2463
0.0254
-0.1189
-0.0529
-0.1837
-0.0383
PointCK1
CK2
CK2
CK3
CK4
CK5
CK6
CK7
CK8
CK9
CK10
CK11
CK12
CK13
0.084 DEV-SQ0.080 STD-DEV
North Sums East Sums
0.204 DEV-SQ0.125 STD-DEV
ΔDistance0.0224
0.0634
0.0312
0.2934
0.0849
0.0316
0.0912
0.1618
0.2469
0.0691
0.1877
0.0685
0.1855
0.1633
0.147 RMS0.0852 STD-DEV0.2934 MAX0.0224 MIN
Point to Points Distance Sums
ComparisonsTITAN to Static Scanning
Accuracies were very similar Static Scanning cleaner data than
mobile More density of points with Static Scan Both have high level of utility Mobile takes dramatically less time to
collect Mobile provides one continuous point
cloud for a corridor Mobile best suited for corridors
Questions?
Thank You.
2009 Spar Conference Denver, Colorado
Mobile Mapping Validation