LiDAR Contour Options Randy Mayden, VP Business Development randym@surdex.com

LiDAR Contour OptionsRandy Mayden, VP Business Development

randym@surdex.com

Surdex Corporation■ Surdex headquartered in St. Louis, MO area■ Over a half-century of photogrammetric mapping

~100 employees8 aircraft – 4 Cessna 441 (Conquest) Turbine Aircraft3 Intergraph Digital Mapping Cameras (DMC)1 UltraCam Xp Wide Angle5 film camerasLeica ALS 50-II LiDAR

■ Very progressive R&DLarge amount of proprietary algorithms and softwareFocus on cost-efficiency and performance

LiDAR ProcessingGPS/IMU

ProcessingIMU

DataReductionGC Check

Position

Attitude

GPS

LASERMeasurements(Range, Angle, Time)

Classification

X,Y,Z

Point Cloud

Stereo QC / Edit

Classified Points (Bare-earth, veg/building)

Stereo

Images

DataThinning

TIN

Break-

lines

DTM

Surface

AUTOMATIC

MANUAL2D Edit

TIN

LASER Intensity,

RGB

Ortho Photos

First Return DEM

Bare Earth DEM Calculations

1. Identify man made structures

• Determine ground elevation at edges

2. Identify vegetated areas

• Search for ground points within area

3. Identify open areas

4. Interpolate between available points

5. Filtering and clean-up

Bare Earth DEM

Automatically extracted Bare Earth DEM

• Ground surface with vegetation and man-made structures removed

• Critical for terrain and hydrology modeling

Bare Earth DEM with 1 meter contours

Raw vs. Edited LiDAR Contours

Contours from raw LiDAR data Contours from raw LiDAR data with photogrammetric edits

Types of LiDAR DTM & Contours

Level I• Classified to bare earth, automated generation

Level II• Classified to bare earth

• Automated, minimal cartographic edits

Level III• Classified to bare earth

• Break lines added to hydrology

• Similar cartographic edits of Level II

Level IV (Specified contour accuracy)• Classified to bare earth

• Full break line enhancement

• Full cartographic edits

Level 1-2 surface

Level 1

Level 1 Surface and Contours

Level 2 Contours

Level 2 Surface and Contours

Level 3 Hydro Breaklines

Level 3 surface

Level 1-2 Surface Level 3 Surface

Level 3 Surface and Contours

Level 3 Contours

Project Area, St. Louis MO

Contours from Bare Earth

Hydro and terrain breaklines

Full break line enforced contours

Full break line enforcement

Contours from LiDAR Data

■ Understand the various data available

■ Understand the cost associated with additional editing and processing

■ Discuss the project requirements with your LiDAR provider

■ Get ready for A LOT of data!