Large Scale Mapping: State-of-art technology in Aerial LIDAR and High Resolution Digital Camera imaging

The US FEMA has prescribed certain formats and standards for LIDAR products. Following are some of the Commercial LIDAR product specifications available to the global users:

High Density LiDAR
0.7 meter average point spacing ; Collection within 40 km baseline Scan frequency and angles based on project specification;¦ Vertical Accuracy: Bare Earth: 15 cm RMSE ; Vegetation: 27 cm RMSE ; Horizontal Accuracy:0.5 meter RMSE ; for bare earth elevation models: 95% of artifacts or more removed depending on terrain and vegetation 98% of all outliers removed ; 97% of all vegetation removed

99% of all buildings removed

Standard LiDAR:
1.4 meter average point spacing ; Scan frequency and angles based on project area terrain and land cover ; Vertical Accuracy: Bare Earth: 18.5 cm RMSE Vegetation: 37 cm RMSE ; Horizontal Accuracy: 1 meter RMSE ; for bare earth elevation models: 89% of artifacts or more removed ;depending on terrain and vegetation ; 90% of all outliers removed ; 90% of all vegetation removed 93% of all buildings removed

Filtering processes for FEMA LiDAR vary from basic LiDAR. When filtering FEMA LiDAR, users can expect artifacts removal at 90 percent or better. About 95 percent of LiDAR collection outliers will be removed. The resulting bare earth model yields 95 percent of all vegetation removed and 98 percent of all buildings removed. Data quality requires the use of cross-flight verification and a single mission calibration as outlined in FEMA’s guidelines and specifications.

LIDAR Application Potentials:
Liar advances and a better understanding of the technology have greatly improved the usefulness of LiDAR as a valuable mapping tool. Potential applications include, but are not limited to, the following:

Flood Mapping and Planning: The high-resolution elevation data provided by LiDAR technology provides valuable insight into flood-prone areas and how

to mitigate flood damage. The Federal Emergency Management Agency (FEMA) has initiated a modernization of floodplain maps throughout the United States using LiDAR data in its Map Modernization initiative.

  • Disaster Management: LiDAR is used to assess damage and support infrastructure rebuilding after a disaster.
  • Coastal Erosion: LiDAR data help detect coastal changes to study and remediate coastal erosion.
  • Aviation Safety: LiDAR is used to identify vertical airfield obstructions to aviation.
  • Forestry: LiDAR can detect forest canopy change to support forest management.
  • Nautical Charting: LiDAR is used to measure seabed depths and topographic elevations for navigation, nautical chartering, rapid environmental assessment and regional costal zone mapping.

Corridor, Network and Land Use Mapping and Planning: LiDAR is used for pipeline right-of-way analysis for oil and gas companies as well as transmission line right-of-way analysis for power companies. Also, network planning can be accomplished for telecom propagation modeling for wireless and mobile network planning. LiDAR data also are used to determine optimal location sites for commercial facilities planning.

Geological: LiDAR detects geological features in heavy vegetated areas such as old-growth forests. Recently, LiDAR has detected faults and karst formations in the Pacific Northwest and Alaska. Reclamation: LiDAR is a valuable tool in quarry projects. Volumetric Studies: LiDAR data are used to determine accurate volumetric calculations for earth work and quarry stock pile inventories. Transmission: Liar is a valuable tool for re-rating and inventory studies for power line resources.

Conclusion:
Developments in Digital Camera imaging, Satellite / Aerial imaging , Lidar, GPS, IMU, Ground Survey equipment and the processing software / hardware have resulted sea change in mapping world and visual information technology. However, many countries are yet to utilize this technology effectively to prepare / update their maps. Global Mapping policies are still restricted and need reformations.

Acknowledgements:
Sanborn company product specs and earlier work done by the company team members are highlighted in this paper.

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