Remote Sensing with a Drone

Remote Sensing with a Droneuse a drone to to derive surface information

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Remote Sensing

Remote Sensingthe science of obtaining information about objects or areas from a distance

Multispectral ImagingRaDAR (Radio Detection and Ranging)LiDAR (Light Detection and RangingSonAR (Sound Detection and Ranging)Photogrammetry

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Electromagnetic spectrumLight is a wave of alternating electric and magnetic fieldsVisible light used in passive remote sensing

http://chandra.harvard.edu/resources/em_radiation.html

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Passive Remote Sensing

Detect natural energy reflected or emitted from observed scene

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photogrammetryPhoto Light, Gramma draw, Metron measureArt, science, and technology of obtaining precise mathematical measurements and three-dimensional (3D) data from two or more photographsUsed for the creation of most topographic maps since the 1930sHighly detailed tw0-dimensional and three-dimensional measurementsTriangulation provides x, y, z coordinate of intersecting lines

photogrammetryX,Y,Z coordinate pairs can be derived for overlapping photos when camera position is known

http://www.clemson.edu/restoration/wlcc/_files/photogrammetry.jpg

Data Collection

Image collection

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Image collection

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Image collection

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Image collection

Images require 80% overlapOblique perspective from image overlapHeight affects resolution & number of imagesSpeed affects image quality JPEG or RAW

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Ground Control POints

Increase Horizontal & Vertical Accuracy by correcting direct georeferencingX, Y, Z coordinate fileIdentifiable in imagesShared by overlapping images Located evenly throughout area of interestCorrect vertical & horizontal position of photos

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Data Processing

Data Processing

Create Spatial DataDrone2Map SoftwareAdvanced Object Detection creating Key Match Points shared by overlapping imagesMosaic overlapping imagesCorrect image X, Y, Z using GCPPhotogrammetry

Georeferenced Overlapping ImagesImage Perspective is Nadir and ObliqueImage matching through advanced object detectionRapid photogrammetric processing and surface detection and ranging15

Products

orthoimageryUniform scale image where corrections have been made for relief displacementShifting pixels towards and away from elevation and principal point

Relief DisplacementCorrected Relief Displacementhttps://www.e-education.psu.edu/natureofgeoinfo/sites/www.e-education.psu.edu.natureofgeoinfo/files/image/keating_left_and_ortho.jpg

Aerial images are not planimetric, they are perspective. Perspective is from principal point, the area directly below camera lens.Goal of Orthorectification is to make the photo consistently planimentric.17

Orthoimagery

18 overlapping (80%) image mosaic - 6,500 matching pointsResolution GSD 3.98cm

: Satellite, Balloon, Aircraft, Boat, Car

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Orthoimagery

18 overlapping (80%) image mosaic - 6,500 matching pointsResolution GSD 3.98cm

: Satellite, Balloon, Aircraft, Boat, Car

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Orthoimagery

18 overlapping (80%) image mosaic - 6,500 matching pointsResolution GSD 3.98cm

: Satellite, Balloon, Aircraft, Boat, Car

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Digital Surface Model

Elevation of natural and antrhopogenic surface

: Satellite, Balloon, Aircraft, Boat, Car

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Digital Surface Model

Elevation (M)

164.70

133.65

fenceconductorsbackstoptrees

: Satellite, Balloon, Aircraft, Boat, Car

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Point cloudSets of X, Y, Z coordinates3d points: 3,231,3513d points per M3: 34.8

Elevation (M)

conductorstreesflood light

: Satellite, Balloon, Aircraft, Boat, Car

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Point cloudSets of X, Y, Z coordinates3d points: 3,231,3513d points per M3: 34.8

Elevation (M)

backstoptreesflood light

: Satellite, Balloon, Aircraft, Boat, Car

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Contours

Slope

Textured Mesh 3d PDFPortable documentGeoreferencedHorizontal and Vertical MeasureDigital markup

: Satellite, Balloon, Aircraft, Boat, Car

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Compare elevation Drone photogrammetry to lidar

Elevation Delta (M)

Area beneath flight is as accurate as LiDAR

Lidar (public available) and PhoDAR are close for flat terrainPhoDAR picked up vegetation and structure not within the lidar point cloud

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Compare elevation Drone photogrammetry to lidar

Elevation Delta (M)

Publicly available LiDAR without overstory returns

Lidar (public available) and PhoDAR are close for flat terrainPhoDAR picked up vegetation and structure not within the lidar point cloud

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AdvantagesFastAccurateCostTemporal

Flight time 5 minutesCollect GPS 15 minutesProcess data 60 minutesTotal time less than 2 hoursCollect 6 acres of surface information

FastPlanning 5 minutesCollect 6 acres of surface information in 5 minutesCollect GPS in 15 minutesProcess data collection 60 minutesTotal collection / process / product time less than 2 hoursCan LiDAR be flown this fast?How long does it take to plan LiDARHow long does it take to plan aerialThere are satellite subscription options

AccurateInitially elevation looks close to LiDAR DTMPublicly available LiDAR did not contain all points, only GroundHorizontal and Vertical corrected with high-accuracy GPS

CheapDrone is ~500Software cost free for trial. Price is unknown, reaching out to our client services.If public data is not availableHow much does LiDAR cost?

TemporalOn Demand Remote Sensing with a DroneLimitations are due to weather and light conditions

Public DataConsider time of collection for publicly available, or for company contracted?Do these data match conditions of event?

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AdvantagesFastAccurateCostTemporal

Elevation comparison shows accuracy close to LiDARPublicly available LiDAR only contained ground returnsHorizontal & Vertical accuracy dependent best available GCP

FastPlanning 5 minutesCollect 6 acres of surface information in 5 minutesCollect GPS in 15 minutesProcess data collection 60 minutesTotal collection / process / product time less than 2 hoursCan LiDAR be flown this fast?How long does it take to plan LiDARHow long does it take to plan aerialThere are satellite subscription options

AccurateInitially elevation looks close to LiDAR DTMPublicly available LiDAR did not contain all points, only GroundHorizontal and Vertical corrected with high-accuracy GPS

CheapDrone is ~500Software cost free for trial. Drone2Map ~3500yrIf public data is not availableHow much does LiDAR cost?

TemporalOn Demand Remote Sensing with a DroneLimitations are due to weather and light conditions

Public DataConsider time of collection for publicly available, or for company contracted?Do these data match conditions of event?

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AdvantagesFastAccurateCostTemporal

Drone is ~500Software cost for Drone2Map ~3500yrsUAS pilot license 150

FastPlanning 5 minutesCollect 6 acres of surface information in 5 minutesCollect GPS in 15 minutesProcess data collection 60 minutesTotal collection / process / product time less than 2 hoursCan LiDAR be flown this fast?How long does it take to plan LiDARHow long does it take to plan aerialThere are satellite subscription options

AccurateInitially elevation looks close to LiDAR DTMPublicly available LiDAR did not contain all points, only GroundHorizontal and Vertical corrected with high-accuracy GPS

CheapDrone is ~500Software cost free for trial. Drone2Map ~3500yrPilot license 150If public data is not availableHow much does LiDAR cost?

TemporalOn Demand Remote Sensing with a DroneLimitations are due to weather and light conditions

Public DataConsider time of collection for publicly available, or for company contracted?Do these data match conditions of event?

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AdvantagesFastAccurateCostTemporal

Near real time Remote SensingSeasonal, Daily, Acute Events

FastPlanning 5 minutesCollect 6 acres of surface information in 5 minutesCollect GPS in 15 minutesProcess data collection 60 minutesTotal collection / process / product time less than 2 hoursCan LiDAR be flown this fast?How long does it take to plan LiDARHow long does it take to plan aerialThere are satellite subscription options

AccurateInitially elevation looks close to LiDAR DTMPublicly available LiDAR did not contain all points, only GroundHorizontal and Vertical corrected with high-accuracy GPS

CheapDrone is ~500Software cost free for trial. Drone2Map ~3500yrPilot license 150If public data is not availableHow much does LiDAR cost?

TemporalOn Demand Remote Sensing with a DroneLimitations are due to weather and light conditions

Public DataConsider time of collection for publicly available, or for company contracted?Do these data match conditions of event?

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ApplicationsConstruction, Environmental, Emergency

Near Real-Time Photos, Videos, and Surface modelingContinuous monitoring only limited by processing rate and battery powerDocument construction site conditions & events of importancePair with existing survey operationPre-During-Post construction planning and remediationWetland DelineationVolumetricsSpans

ConstructionDocument construction conditionsUse surface information to document asbuilt conditionsPair with survey to gain synergyNear Real-Time

EnvironmentalPre and Post construction for planning and remediationNear Real-Time

EmergencyNear Real-Time Photos, Videos, and Surface modelingContinuous monitoring only limited by processing rate and battery power34

Follow UpRobust ComparisonsCollection MethodologyProcessing MethodologyPublic DatasetsHorizontal & Vertical Accuracy

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Thank You