Teng Peng SEANG, PGEC, Phnom Penh, Jan-Peter MUND (GTZ-CIM)

Geo-referenced Balloon borne Digital Aerial Photo Technique

A low cost high-resolution optionfor developing countries

2 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Content and Introduction

The Problem Technical solutionsGeo-referencing and GPS post processingFirst promising field resultsExamples of Applications:o Kampong Speu - Regional Planning

and Forest Mappingo Battambang - Urban Planning

Conclusion

3 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

The problem:Data accessibility and exhibiting regional maps

4 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Problem background

Most recent high resolution aerial photos or RS imagery is not yet available on regional or local levelData accessibility is complicated, due to several administrative procedures and authorizationInitiating a large informal market for GeodataHigh resolution RS imagery like Google Earth, Quickbird, Ikonos are not available on the local level.

Consequences: Regional and local planning measures are lacking recent land cover and land use dataKeeping geospatial-databases up to data becomes rather impossible

5 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Applied technical solutions

Exercise out dated aerial photo ?Applying low resolution RS imagery (Spot) ?Processing administrative requests with doubtful results ?Collecting essential data via field surveys ?Accomplish land use planning without latest land cover data ?Looking for enhanced applied solutions !i.e.: Geo-referenced balloon borne digital aerial pictures of planning and survey areas

6 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

The solution: Balloon borne digital aerial pictures acquisition

7 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

The Challenge: Simple technical solution, available in Cambodia

Digital Camera: Olympus CAMEDIA C70 7..2 Mega 1 light GPS receiver Infrared timer 4 Handheld GPS Garmin76CSMap for GCP’s

Inflatable balloon made of thin, strong PE materialFixed with 8 thin fishing lines, easy to handle and controlFlexible and uncomplicated for transportation

8 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Balloon Application Technique

Balloon gas = HydrogenLocal production at the site: Aluminium cans +Natriumhydroxide + Water (AL+NaOH+3H2O= Na[AL(OH)4]+1,5H2O)=> Hydrogen + Natriumaluminat

Application via the Phnom PengGeoMatics Education Centre in Phnom PenhCustom orientated cheap application:

o 200 $ per km² at 1-5 pictures only o 150-170 $ per km² with more then

5 pictures in one region

9 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Data acquisition and post processing

Flight planning Field application Data acquisition Preparing of image mosaics

10 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Image processing

Standardized RS Data enhancement methods applied:o Haze correctiono Mosaic Colour adjustment o Image mosaics o Cloud maskingo Image adjustmentso Relative geo-referencing of

mosaicsto GPS - GCP’sSpot imagery Topo MapsAny other existinggeospatial data

11 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Geodetic cartographic issues

Cambodian geodetic trigonometric network not fully established on local and regional levelNational topographic network not yet build No homogeneous horizontal datum applied yet (Indian 54, Indian 60 and WGS 84 are permanently used)Indian 54, Indian 60 and WGS 84 according to origin and history of the topographical surveyPermanent GCP’s missing for accuracy enhancementSurvey of GCP’s with handheld GPS Accuracy correction via post processing method

12 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Battambang:Urban and district planning project

1: 5.000

1: 1.000ca. 1: 75.000

13 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Scale per pixel:o Pixel scales according to platform altitude o 1: 10 cm up to 1: 200 cm

Geo-referenced relative accuracy:o To Spot Imagery 2-3 pixel => 30-50 cmo To Topo Maps at 1:50.000 scale < 1mo To single handheld GPS – Data (5-10 m)

Promising results at planning scale

14 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Establishment of recent regional planning datasets and maps

15 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Monitoring seasonal and intra seasonal vegetation and cropping pattern

16 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Further applications ahead

Battambang District – Housing for the Poor: o UNESCAP project on Improving informal settlements

Kampong Speu, Kandal and Pursat provinces:o Monitoring reforestation o Detailed Vegetation biodiversity and structure surveyso Monitoring and improvement of road network and

bridge infrastructure o Small scale irrigation project planning

Technical development:o Application on ultra lights and delta gliderso Oblique image technologyo Application of scanners with higher resolution

17 FIG - 2006 TS 73.2: T.P. SEANG & J.-P. MUND: Geo-referenced Balloon Digital Aerial Photo Technique

Conclusion

Geo-referenced balloon borne digital aerial photos could provide: o Low costo Simple and flexible applications for o High resolution imagery at regional and local

planning scaleso With data processing options at desktop PC

levelo Avoiding complicated and cost intensive

administrative procedureso Without having the purpose to provide most

accurate cadastral surveying data.

Teng Peng SEANG, PGEC, Phnom Penh, Jan-Peter MUND (GTZ-CIM)

Thank you very much for your attention

Teng Peng SEANG, Phnom Penh Geomatics Education Centre, PGEC,0122880878@mobitel.com.kh

Jan-Peter MUND (GTZ-CIM)jpmun03@yahoo.com