drones / suas unmanned aircraft systems at the flood control … · 2ft contours with orthophoto...

Drones / sUASUnmanned Aircraft Systems at the Flood Control District

Drone Mapping

Joe Wagner

Mapping, Surveying, & CAD Manager

Engineering Division

Greywolf Drone 1986

Greywolf Drone 1986

Greywolf Drone 1986

• 17ft wingspan

• 15ft in length

• 38 hp motorcycle engine

• Catapult launched

• Infrared and daylight camera

Potential UAS use at the District

• Storm event inspection/documentation

• Surveying/mapping for engineering and design

• Volume calculations for construction projects

• Inspections:

– Dams, Levees

– Bridges

– Construction Management monitoring

– Property inspections and appraisals

Drone types

• Multi Rotor

• Fixed Wing

Project Planning

• Define project site and estimate ground control

Ground Control

• Set aerial targets across project site

• Low and high spots

• Horizontal and vertical

X = easting

Y = northing

Z = elevation

Mission Planning• Drone mission

planning apps such as DroneDeploy, PIX4D, and DJI GO

• Create flight parameters such as speed, altitude, image overlap based on specifications

Mission Planning• 18 acres

• 11 min 46 secs flight time

• 159 images

• 200ft AGL

• 80% forward overlap

• 80% side overlap

• 1 battery

• 15 mph

Photogrammetric processStereo pairs are made up of overlapping images – 80% - 159 images

Photogrammetric processStereo pairs are made up of overlapping images – 80%

Photogrammetric process

Photogrammetric mapping was doneusing 9” x 9” film in black and whiteAt a scale of 1” = 800’.

Photogrammetric process

• Each image taken from the drone is georeferenced using it’s onboard GPS.

• The Bentley ContextCapture software imports each image into their proper location.

• The aerotriangulation process aligns each image and calculates tie points between each image. It looks for like pixels between images.

• ContextCapture merges each image to create the 3D mesh and associated data.

Drone Flight

Drone Flight

Data output

• Vertical accuracy is approx. 2-4 cm

• Individual images – stereo pairs

• 3D mesh

• Orthophoto - georeferenced

• RasterDEM tif - georeferenced

• Digital Surface Model (DSM) pointcloud LAS file

• Contours

• Video – 4K mp4 or mov formats

Output Data From Flight

• 3D mesh

3D mesh flythrough

3D mesh of rock slide area

3D mesh TIN

3D mesh

3D mesh created from Nikon DSLR images

Aerial LiDAR pointcloud

Aerial LiDAR pointcloud

Drone derived pointcloud

Full LiDAR Bare earth LiDAR

Drone derived 2ft contours

2ft Contours with orthophoto 2ft Contours

Orthophoto comparison

County ortho.32’ pixel resolution

Drone ortho.7” pixel resolution

Orthophoto comparison

County ortho.32’ pixel resolution

Drone ortho.7” pixel resolution

3D pointcloud from drone

Each pixel represents X,Y, and Z values3D pointcloud with RGB values on each point

3D pointcloud from Leica C10

3D pointcloud with RGB values from terrestrial ground scanner - notice shadows from vegetation and ground above scanner.

Siphon Draw Fissures Flight

Siphon Draw Fissures Flight

Siphon Draw Fissures Flight

Siphon Draw Fissures Flight

Siphon Draw Fissures Flight

Without ground control With ground control

Siphon Draw Fissures Flight

Drone flight with ground control

County orthophoto

Siphon Draw Fissures Flight

Weir pointcloud Fissure pointcloud

Question?

Joseph Wagner

Mapping, Surveying, & CAD Manager

Engineering Division

Flood Control District

2801 W Durango St, Phoenix, AZ 85009

602-506-2203 Office

623-297-2638 Cell

josephwagner@maricopa.gov