2010 LiDAR Collection in West Virginia’s Coal Fields

1. 2010 LiDAR Collection in West Virginia’s Coal Fields West Virginia GIS Conference June 9, 2010

2. AOC and future mining  LiDAR

3. LiDAR collection specifications • Horizontal postings: 1 meter • Vertical accuracy: 15 centimeters • Additional derived data products include: • ESRI elevation grid • Hillshade • 2 foot contours used in AML program • Intensity image  useful in QCing LiDAR data • ~ 2 TB of data before derived products

4. LiDAR Technology LiDAR = Light Detection And Ranging • Capable of emitting 100,000 pulses per second at altitudes less than 1,100 meters • Day or night operation • Capable of collecting millions of elevation points per hour • All digital: no intermediate steps to generate digital XYZ • Rapid turnaround: Capable of processing within a week • Multiple returns per pulse • Airborne: Easy to mobilize and demobilize • Non-Intrusive: capable of accessing remote areas • Solid state Class IV laser • Swath width: Variable; 0 to 0.93 x altitude (m) • Horizontal Accuracy: 1/2000 x altitude • Elevation Accuracy: +/- 15 cm (or better) • Typical spot center spacing is from 0.5 m to 5.0 m

5. Workflow • Acquisition NOAA Processing Product

6. Flight Planning • Pulse rate frequency (PRF) • Scan frequency • Scan angle • Desired overlap • Altitude • Make sure above parameters yield an acceptable resolution

7. Acquisition Process • Pre-Flight • Check aviation weather • Review day’s mission with pilots and ground crew • In Airplane • Check system • Power up • Communicate with ground control operator • Initialize GPS/IMU • In Flight • Transit to project area • Begin collection • Constantly monitor conditions during collection • Keep flight log • Post Flight • Final initialization on GPS/IMU • Power down • Retrieve removable hard drives for data decoding and processing

8. Ground Control Two Topcon Hiper dual frequency static GPS receivers equipped w/ FC-100 controllers. 20 channel integrated GPS receiver Signals Tracked – L1/L2 C/A Code and P Code (dual frequency) 76 mb of Memory Advanced Multipath Reduction Logging Intervals of up to 20 times per second (20Hz) Horizontal – 3mm + 0.5ppm Vertical – 5mm + 0.5ppm Cold Start - < 60 sec Warm Start - < 10 sec Reacquisition - < 1 sec

9. Ground Control Ground GPS Requirements • Base station must be within 30 km (18 miles) from airborne laser. • Use dual frequency GPS receivers. • Use two highly accurate published geodetic control points during airborne data collection to provide redundancy. • PDOP of 4 or less, optimal 3 or less. • Data collected from at least 6 satellites at 1 second epochs. • Base stations must have a clear view of the sky with limited mulitpath.

10. GPS Planning

11. SBET

12. Processing Workflow ALTM Storage Download Hard Drive QC Data Extract / Decode Laser Data File Process GPS IMU Information Raw Laser Data PosPac Compute Laser Points Output Laser Points Microstation

13. Calibration

14. Building an ICI (=isolated computing island) • Isolates one or more VERY high performance computers from central IT C&C duringVERY long compute jobs: • No pushes of server OS upgrades • … followed by the requisite reboots • Isolate from dependence for TIPS licenses via pool of WVDEP licenses  network outages • Enough local storage to create a peer-to-peer within-the-room network • UPS on each PC

15. PC specs HP800 workstations with 64 bit OSes  super modular. Single quad core CPUs  5th fastest on the planet when we purchased the boxes 16 GB RAM & 6 TB each local storage 4 megapixel displays + CUDA card Isolated peer-2-peer network when working off the net Gigabit network connections for on Net Local licenses of all core apps

16. Qcing LiDAR and LiDAR software • QCing LiDAR deliverables • 2003 Statewide GCPs file • Multiple LiDAR datasets that overlap  difference grid calculation • Trimble R8 GNSS receivers for spot checks • Outsource via FEMA monies • Software  64 bit, use multicores • Virtual Geomatics • Applied Imagery’s Quick Terrain Modeler

17. WV CORS

18. The end