Departement Bau Vermessungsamt - UAV-G 2013 Eisenbeiss_Web.pdf · Departement Bau Vermessungsamt Evaluation of UAV-based orthoimages for the use in cadastral mapping H. Eisenbeiss,

Departement BauVermessungsamt

Evaluation of UAV-based orthoimages for the use in cadastral mapping

H. Eisenbeiss, M. Sauerbier , Ch. Wildi

September 4, 2013

Demo at UAV-g 2011


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Content

• Introduction

• Motivation/Restriction

• Traffic education area for children “Verkehrsgarten”

• Cemetery Oberwinterthur (City of Winterthur)

• Conclusion


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Campus Science City Hoenggerberg, ETH Zurich; UAV-g (2011) (R-Pod)

Thanks to the organizers UAV-g 2013 in Rostock!


City of Winterthur

Land registry office§ Geoinformatics§ Surveying

Surveying section is responsible § Cadastral surveying§ Control of construction survey

In addition we offer different kind of surveying in Winterthur§ Monitoring of construction / construction sites§ Engineering survey§ Terrain measurement …

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Motivation§ Use of UAVs for cadastral mapping of

§ Parks§ Street sections (Planning and updating the map after construction)§ Waste disposal areas

§ Updating 3D City Models§ Main buildings in the city

§ First results about the accuracy of extraction of geometriespresented at UAV-g 2011(Manyoky et al.)

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Cadastral restrictions in Switzerland

Art.3 TVAV• TS1: Central business districts

• TS2: Built-up areas and construction zones

• TS3: Intensively used agricultural and forested areas

• TS4: Extensively used agricultural and forested areas

• TS5: Alpine and non-productive areas

TS2 (HXE)Lateral accuracyLand cover and single objects 10cm

Land ownership

Not exactly defined point

3.5cm

20cm

Height accuracy

Height (DTM 2m Grid)

Not exactly defined terrains

80cm

200cm

Standard Standard deviationdeviation forfor thethe zoneszones TS2 of TS2 of thethe Swiss TVAVSwiss TVAV


Traffic education area city of Winterthur

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• Stitched image (8 images) à first overview of the area of interest

• Data acquisition was done using a UAS md4-200 from microdrones


Traffic education area city of Winterthur• The stitched image was used in combination with the field notes for the

interpretation/ processing of the measurement data acquired with total

station and GNSS (office work)

• Image is used for the definition and visualization of the bicycle trainings

tracks


Traffic education area city of Winterthur: Map showing infrastructure and green areas




Traffic education area city of Winterthur: Webpage @ city of Winterthur


Cemetery Oberwinterthur

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Starting position

• Request from the city gardeners of Winterthur concerning the

documentation of regenerated and renewed parks, including cemeteries

• Particularly the cemetery Oberwinterthur was an object which had to be

documented in April 2013

à Updating cadastral map and documentation of the inventory


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UAS: Falcon 8 (Ascending Technologies)

Remote Control Futaba FX-30

Falcon 8Astec Autopilot


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Data acquisition

• Definition and measurement of the GCPs using GNSS

• Autonomous UAV flight

• Flying altitude 70 m

• Ground resolution 1.5 cm/Pixel

• Camera calibration on-site

• 5 minutes flight time

• Documentation of all required structures using GNSS and a total station

(Trimble )

• 3 days work (one experienced surveyer)

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Overview GCPs

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UAV image processing

§ Image orientation§ Camera calibration with iWitness§ Import of onboard IMU and GPS data à initial orientations§ Automatic tie point measurement was successful§ Manual corrections (errors at road markings, tree areas)

§ Results§ σ0= 0.23 Pixel § RMSE of GCPs less than 0.3 cm

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Orthoimage generation

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§ Mosaic Pro (LPS) was used§ Existing DTM

§ Additional manual measurements at slope areas, walls and steps

§ Automated seamline generation§ Manual editing of seamlines



Cemetery Oberwinterthur (results)


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Cemetery Oberwinterthur (results)


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Erste Ergebnisse



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Results

• Automatic image orientation (mfb geoconsulting) (1/2 day)

• Orthoimage generation (1 day)

• Analysis of the orthoimage and corrections including additional manual

measurements of seed points, vectors etc. (2 days)

• Compared to vector data the main differences occur on walls, slops and

vegetation etc.

• à Accuracy in general 1-5 cm (max. 20cm)

• GNSS/Total station or UAS ?


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Conclusions

§ UAV orthoimages have a great potential for § Specific restricted zones of interest in city areas§ A fast overview; web presence and commercial and

additional information for example: Documentation of a construction site

§ For cadastral mapping you need to check the completeness and correctness of the data (particularly for unknown areas)

§ Fast data acquisition

§ Commercial/open software package and knowledge are necessary


Acknowledgments

§ IGP ETH Zurich (David Novák, Piotr Tokarczyk)§ Omnisight (Emil Siegrist)

Thank you for your attention!

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Documents

Departement Bau Vermessungsamt - UAV-G 2013 Eisenbeiss_Web.pdf · Departement Bau Vermessungsamt Evaluation of UAV-based orthoimages for the use in cadastral mapping H. Eisenbeiss,