the challenges of using remote sensing imagery in gis - Malaysia ...
the challenges of using remote sensing imagery in gis - Malaysia ...
the challenges of using remote sensing imagery in gis - Malaysia ...
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THE CHALLENGES OF USING REMOTESENSING IMAGERY IN GIS4 th National GIS conference and Exhibition (NGIS) 2010PICC29 th June 2010NIK MAZLINA NIK MUSTAPHAMALAYSIAN REMOTE SENSING AGENCYMOSTI
SPATIAL RESOLUTIONRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
QuickBird (0.67 m) Ikonos (1 m) SPOT-5 (2.5 m)SPOT-5 (5 m) SPOT-5 (10 m) Landsat-5 TM (30 m)SCALE 1:2,300
QuickBird (0.67 m) Ikonos (1 m) SPOT-5 (2.5 m)SPOT-5 (5 m) SPOT-5 (10 m) Landsat-5 TM (30 m)SCALE 1:3,500
QuickBird (0.67 m) Ikonos (1 m) SPOT-5 (2.5 m)SPOT-5 (5 m) SPOT-5 (10 m) Landsat-5 TM (30 m)SCALE 1:10,000
QuickBird (0.67 m) Ikonos (1 m) SPOT-5 (2.5 m)SPOT-5 (5 m) SPOT-5 (10 m) Landsat-5 TM (30 m)SCALE 1:25,000
QuickBird (0.67 m) Ikonos (1 m) SPOT-5 (2.5 m)SPOT-5 (5 m) SPOT-5 (10 m) Landsat-5 TM (30 m)SCALE 1:50,000
SPECTRAL RESOLUTIONRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
• The number <strong>of</strong> spectral bands <strong>the</strong> satellite sensor recordsdata• Landsat TM sensor has 7 bands while Spot-5 has 4 bands• Landsat TM image have greater spectral resolution thanSpot-5 image
SPOT SPECTRAL BANDSB1 (Green) B2 (Red) B3 (Near-IR) B4 (SWIR)• Several spectralbands isnecessary todist<strong>in</strong>guishbetween differentmaterials on <strong>the</strong>image
SPOT : Bands 432 (RGB)SPOT : Bands 342 (RGB)
LANDSAT-5 TMSPECTRAL BANDSBand 1Band 4Band 2Band 5Band 3Band 6Band 7
Landsat TM: Bands 321 (RGB)Landsat TM : Bands 432 (RGB)
Landsat TM : Bands 432 (RGB)Landsat TM : Bands 543 (RGB)
Landsat TM : Bands 453 (RGB)Landsat TM : Bands 543 (RGB)
RADIOMETRIC RESOLUTIONRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
• Radiometric resolution describes <strong>the</strong> capability <strong>of</strong> <strong>the</strong> image tostore data/<strong>in</strong>formation• A simple analogy: a 5 MegaPixel camera is much more capable<strong>in</strong> captur<strong>in</strong>g details & features compared to a 1 MegaPixelcamera.2-bit image8-bit image
Example : IKONOS is 11-bit data and SPOT is 8-bit data.In a 11-bit image, features <strong>in</strong> shadowed regions are still visiblecompared to shadowed regions <strong>in</strong> an 8-bit imageIKONOS : 11-bitSPOT : 8-bit
TEMPORAL RESOLUTIONRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
• The frequency <strong>of</strong> satellite overpass at <strong>the</strong> same locationLandsat TM satellite look<strong>in</strong>g at nadirSpot satellite look<strong>in</strong>g at nadirdate 1 date 2date 1 date 216 days26 days• The Spot satellite system<strong>in</strong>creases <strong>the</strong> ability toacquire images by <strong>the</strong> use <strong>of</strong><strong>of</strong>f-nadir view<strong>in</strong>gSpot satellite look<strong>in</strong>g at <strong>of</strong>f-nadirdate 1 date 25 days
SPOT-5 Orbital Calendar9 Sept14 Sept19 Sept
SWATH WIDTHRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
NOAA swath 4800 km 2600 km
Landsat swath= 185 km 185 km
LandsatNOAA swath compared to Landsat
SPOT swath= 60 km 60 km
SPOTSpot swath vs.Landsat
QuickBird swath= 16 km 16 km
QuickBirdQuickBird swath vs. Spot
Type <strong>of</strong>SatelliteSpatial Resolution(meters)Swath Width(Geographic Coverageper Image)# spectralbandsFrequency <strong>of</strong>Repeat Coverage<strong>of</strong> Same LocationRadiometricLOW(NOAA)resolution 1100m 2700 km swath 5 bands 1-2 days 8 bits(MODIS)resolution 250m, 1000m 2300 km swath 36 bands 1-2 days 8 bitsMEDIUM(LANDSAT TM)resolution 15m, 30m 183 km swath 7 bands 15-30daysHIGH8 bits(SPOT5)resolution 2.5m, 5m, 10m 60 km swath 4 bands 15-30days8 bits(GEOEYE-1,IKONOS)resolution 0.5m, 1m ~10 km swath 4 bands Months toyears11 bits
How Satellite Imagery Benefit GIS?SATELLITE IMAGERYCAPABILITIESSystematic image collection(frequent repeat coverage)Synoptic observations(wide swath)Multi spectral observationsmakes GIS real timeGives GIS a source<strong>of</strong> <strong>in</strong>formation forgeneration & revision<strong>of</strong> geospatial dataGreatly enhanced aGIS mapp<strong>in</strong>g projectVarious spatial resolutionRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
THE CHALLENGES IN THESUCCESSFUL USAGE OFIMAGERY IN A GISRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
MAKE THE IMAGERY GIS-READY Image must be re<strong>gis</strong>tered to specificplaces on <strong>the</strong> earth• simple geometric transformation to fit<strong>imagery</strong> to <strong>the</strong> vector database• for precise mapp<strong>in</strong>g, image must beorthorectified and adjust <strong>the</strong> projection<strong>of</strong> <strong>the</strong> vector data to match that <strong>imagery</strong>Remote Sens<strong>in</strong>g <strong>Malaysia</strong>
EXTRACT INFORMATION FROM IMAGERY By means <strong>of</strong> image analysis <strong>us<strong>in</strong>g</strong> imageprocess<strong>in</strong>g techniques• visual process<strong>in</strong>g - image <strong>in</strong>terpretation<strong>us<strong>in</strong>g</strong> colour, size, shape, texture, pattern,site & association
• digital process<strong>in</strong>gSpectral enhancement, image classification – spectralclassification, pattern recognition, textural analysisand change detection
To automate <strong>in</strong>formation extraction from ahigh resolution <strong>imagery</strong> require computerbased expert system
LARGE SIZE OF IMAGE DATA A s<strong>in</strong>gle snapshot image is alwayshundreds <strong>of</strong> megabytes Image mosaic cover<strong>in</strong>g a state can behundreds <strong>of</strong> gigabytes The higher <strong>the</strong> spatial, spectral andradiometric resolution, <strong>the</strong> larger <strong>the</strong>file size Requires high storage and process<strong>in</strong>gcapacity
ACCESS IMAGERY IN A TIMELY MANNER Many GIS applications require recent<strong>imagery</strong>. If its not archived, <strong>the</strong> imagehas to be acquired The downside - to acquire cloud-freeimages <strong>in</strong> a humid tropic country like<strong>Malaysia</strong> takes a long time
10-01-2010 25-02-201026-01-2010 26-02-201005-02-2010 03-03-201021-02-2010 24-03-2010
RECENT DEVELOPMENT &RECOMMENDATIONS TOADDRESS THE CHALLENGESRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
standard GIS s<strong>of</strong>tware <strong>in</strong>corporateswizard based user <strong>in</strong>terface for users tocreate own ortho<strong>imagery</strong> Orthorectified <strong>imagery</strong> products fromRemote Sens<strong>in</strong>g <strong>Malaysia</strong> current GIS s<strong>of</strong>tware provide an easy touse <strong>in</strong>tuitive image process<strong>in</strong>g andanalysis tools that enable users toextract <strong>in</strong>formation quickly and easilyRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
hands-on-tra<strong>in</strong><strong>in</strong>g on image process<strong>in</strong>gand analysis by Remote Sens<strong>in</strong>g<strong>Malaysia</strong> compromise large size high resolution<strong>imagery</strong> with medium resolution image compression ECW/ JPEG 2000format for efficient storage <strong>of</strong> <strong>imagery</strong>Remote Sens<strong>in</strong>g <strong>Malaysia</strong>
utilize Image Web Server for handl<strong>in</strong>g<strong>imagery</strong> and a GIS map server for <strong>the</strong>vector layers cloud comput<strong>in</strong>g and image stream<strong>in</strong>gtechnology Remote Sens<strong>in</strong>g <strong>Malaysia</strong> providecustom image acquisition - user canplan acquisition dur<strong>in</strong>g <strong>the</strong> month <strong>of</strong>good wea<strong>the</strong>rRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
CONCLUSION <strong>the</strong> advancement <strong>of</strong> ICT, <strong>remote</strong><strong>sens<strong>in</strong>g</strong> and GIS technology aremeet<strong>in</strong>g <strong>the</strong>se <strong>challenges</strong> satellite <strong>imagery</strong> will cont<strong>in</strong>ue to growas an important source <strong>of</strong> geospatial<strong>in</strong>formation for GISRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
THANK YOUfor enquiries, please contactmazl<strong>in</strong>a@<strong>remote</strong><strong>sens<strong>in</strong>g</strong>.gov.myor visit http://www.<strong>remote</strong><strong>sens<strong>in</strong>g</strong>.gov.myRemote Sens<strong>in</strong>g <strong>Malaysia</strong>
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