1. UAV BASED REMOTE
SENSING OF A LANDSLIDE
103119006 - Adithya A
103119011 - Amit V
103119036 -
Bhuvaneswari G
103119038 - Saiuddiep
G
103119078 - Varun
Kumar P
103119084 - Tanvi Sri
Vardhan P
103119113 - Sharan B
TEAM MEMBERS
2. ● A UAV or unmanned aerial vehicle, commonly known as a
drone is an aircraft, without a human pilot on board and a
type of unmanned vehicle
● The use of UAV drones for civilian purposes especially for
mapping includes thematic mapping for agriculture, forestry,
archeology and architecture, environment, emergency
management and traffic monitoring
● Drones can be used in applications that require high spatial
and temporal resolution. They become cost effective and
efficient alternative to satellite remote sensing in such
cases.
INTRODUCTION
4. SOME INTERESTING APPLICATIONS
OF DRONES IN SURVEYING
Irrigation mapping
and monitoring
Hazard Assessment
Precision
Agriculture
Infrastructure
monitoring
2 3
1 4
5. OBJECTIVE OF THE STUDY
● To monitor hazards from active landslides and to understand the processes involved using
drones
● To measure both spatial and temporal measurements such as displacement rates and extents
and changes in the surface topography using drones for landslide investigations
● To identify the fixed areas of persistent deformation, producing fissures of different
distributions and orientations and relating directly to the bedrock topography.
● To evaluate the UAV capability for imaging fissures and displacements on the landslide surface
and to assess the subsequent image processing approaches for suitably georectifying the data
6. METHODOLOGY OF THE STUDY FOLLOWED
Drone path planning & GCP
determination
Collecting drone images
Base Map
Ortho mosaic and DTM
Generation
Rectification
Orthomosaic Accuracy Test 3D Modelling and Contour Generation
Situation Map
7. EXPLANATION OF THE WORK
● Capable of flying in difficult alpine terrain
● More stable with less in-flight vibration and no need for a large, variable pitch rotor-unit
● Inertial measurement units (IMUs) : 3 acceleration sensors, 3 gyroscopes, a three-axis
compass, and a pressure sensor, regulated by basic PID (proportional integral differential) loops
● Lithium polymer battery of ~5.0 A.
● A light weight low-cost digital compact camera for image acquisition
Challenges :
● Highly skilled pilot
● Control range of a few hundreds of metres
● Small payloads, UAV-reliability and the restricted radio bandwidth for
ground communication
A) UAV SPECIFICATIONS
8. ● The study was carried out on the Super-Sauze
landslide, located on the north-facing slope of the
Barcelonnette Basin(Southern French Alps).
● The Landslide mainly consists of Jurassic black
marls and has a total volume estimated at 750,000
m3.
● A UAV flight campaign encompassing the whole
sliding region (850× 250 m) of the Super-Sauze
landslide was carried out in October 2008, resulting
in 1486 airborne photographs.
.
B) PROCESS OF WORK DONE
9. ● To enable the images to be
georeferenced, 199 targets(~0.4 × 0.6
m rectangular coloured sheets to
ensure visibility) were deployed over
the landslide as ground control points
(GCPs), and their centroid locations
determined with differential GPS
(DGPS)
● To compare the UAV results with
ground-based data, the topography of
the toe-region of the slide was scanned
with a terrestrial laser scanner.
10. DATA PROCESSING
Drone
Images
Ortho-mosaic Generation
Rectification
for optical
distortions
Transformatio
n to GCP
coordinates
Merging and
Color
Correction
Digital Terrain Model (DTM)
Generation
Generated using imaging
matching algorithms
(GOTCHA) and
photogrammetric
principles (VMS)
12. DATA ACCURACY
● Errors within the georeferencing of the
ortho-mosaic were quantified by
comparison of all 199 GCP locations to
their DGPS - measured location
● The quality of the photogrammetric
DTM was assessed by subtracting the
overlapping TLS DTM
● Horizontal offsets were determined by
image matching
13. Horizontal displacement analysis of the toe-region between the airborne ortho-photo of May 2007 (A)
and the UAV-based ortho-mosaic of October 2008 (B).
RESULTS
14. Principal fissure types: shear fissures, cross-shaped fissures, longitudinal fissures and transverse fissures
identified in the ortho-mosaic 2008 of Super-Sauze landslide.
15. SUMMARY OF THE WORK
● A study was carried on the landslide area that needs to be imaged and suitable locations for takeoff and
landing of drones were identified.
● Ground control points(GCPs) were deployed to enable Geo-referencing of the images of taken by the
drone
● The images by drone (UAV) are processed and ortho-rectified using VMS software to get UAV imagery
● To allow comparison of the UAV data with these other sources, two processing procedures were carried out;
○ Generation of an orthomosaic
○ DTM construction of selected areas using close range photogrammetry techniques.
● Errors within the georeferencing of the ortho-mosaic were quantified by comparison of all GCP locations to
their Differential GPS measured locations
● Finally UAV-based displacement analysis of the landslide and identification of tension & desiccation cracks
and fissures are present on the surface of the landslide was carried out by comparing the ortho-mosaic with
the aerial ortho-photo in a geographical information system (GIS).
● In this study it was shown that a low-cost UAV-based remote sensing approach reveals high-resolution
16. RECOMMENDATIONS AND
INFERENCES
● Use of an autonomously controlled UAV is recommended as manual control of the UAV led to
deviations in flight altitude which leads to with changing ground resolutions per pixel
● The radio controlled UAV used in this study requires the presence of a highly skilled pilot and
limits the operational area to the control range of a few hundreds of metres. There are also
challenges related to the relatively small payloads, UAV-reliability and the restricted radio
bandwidth for ground communication
● UAV acquired images are more preferred since TLS data are subject to shadowing due to the
oblique view point.
● UAV based surveying is more viable when high temporal and spatial resolution is required.
Operating satellite’s for such high resolution will be economically infeasible and inefficient.
17. REFERENCES
● Niethammer, U., James, M., Rothmund, S., Travelletti, J., & Joswig, M. (2012). UAV-
based remote sensing of the Super-Sauze landslide: Evaluation and results.
Engineering Geology, 128, 2–11. https://doi.org/10.1016/j.enggeo.2011.03.012
● Niethammer, U., Rothmund, S., Schwaderer, U., Zeman, J., & Joswig, M. (2012,
september). OPEN SOURCE IMAGE-PROCESSING TOOLS FOR LOW-COST UAV-
BASED LANDSLIDE INVESTIGATIONS. The International Archives of the
Photogrammetry, Remote Sensing and Spatial Information Sciences, 161–166.
https://doi.org/10.5194/isprsarchives-xxxviii-1-c22-161-2011
