<ul><li>Flood modelling and management </li></ul><ul><li>Glasgow University  </li></ul><ul><li>8 September 2004 </li></ul>...
<ul><li>Format for morning session </li></ul><ul><li>9-30 – 10.30 Comparison of modern data collection technologies </li><...
<ul><li>How important are heights in flood modelling? </li></ul>
<ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Ae...
<ul><li>Comparison of data collection technologies </li></ul><ul><li>For each technology a summary on </li></ul><ul><li>Pr...
<ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Ae...
<ul><li>GPS </li></ul><ul><li>Process </li></ul><ul><li>Use technique called RTK or kinematic </li></ul><ul><li>Requires b...
<ul><li>GPS </li></ul><ul><li>Potential sources of error  </li></ul><ul><li>Grid transformation and geoid model –  Link </...
<ul><li>Benefits </li></ul><ul><li>Accurate to 10mm </li></ul><ul><li>Certainty with ground heights </li></ul><ul><li>Accu...
<ul><li>GPS </li></ul><ul><li>General comments </li></ul><ul><li>Many UK companies  -  Link </li></ul><ul><li>In GB OS hav...
<ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Ae...
<ul><li>Aerial Photography </li></ul><ul><li>Process </li></ul><ul><li>Route planning; weather forecasting; flying permiss...
<ul><li>Aerial Photography </li></ul><ul><li>Potential sources of error  </li></ul><ul><li>Crabbing, fore and aft overlap ...
<ul><li>Concerns </li></ul><ul><li>Flying permission required </li></ul><ul><li>Seasonal </li></ul><ul><li>Weather depende...
<ul><li>Aerial Photography </li></ul><ul><li>General comments </li></ul><ul><li>Was used by the EA – replaced by LIDAR in ...
<ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Ae...
<ul><li>LIDAR </li></ul>
<ul><li>LIDAR </li></ul><ul><li>Process  </li></ul><ul><li>Route planning; weather forecasting; flying permission; control...
<ul><li>LIDAR </li></ul><ul><li>Potential sources of error include </li></ul><ul><li>GPS and IMU calibration </li></ul><ul...
<ul><li>Benefits </li></ul><ul><li>Accurate to 50mm </li></ul><ul><li>Large areas covered in one flight (30 sq km in one h...
<ul><li>LIDAR </li></ul><ul><li>General comments </li></ul><ul><li>4 UK companies – global directory at  ( Link ) </li></u...
 
<ul><li>Coffee break </li></ul>
<ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Ae...
<ul><li>SAR </li></ul><ul><li>Process (InterMap) </li></ul><ul><li>Aircraft has 2 antennae, receive slightly different ret...
<ul><li>SAR </li></ul><ul><li>Potential sources of error </li></ul><ul><li>Shadow </li></ul><ul><li>Rain shadow </li></ul>...
<ul><li>Benefits </li></ul><ul><li>Can cover 100 sq km in a few hours </li></ul><ul><li>Generates height (up to 0.3m) and ...
<ul><li>SAR </li></ul><ul><li>General comments </li></ul><ul><li>No UK companies </li></ul><ul><li>Accuracy comparison by ...
<ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Ae...
<ul><li>Multi Spectral Satellites Imagery </li></ul><ul><li>Process  </li></ul><ul><li>Order and collect basic imagery </l...
<ul><li>Multi Spectral Satellites Imagery </li></ul><ul><li>Potential sources of error  </li></ul><ul><li>Cloud </li></ul>...
<ul><li>Multi Spectral Satellites Imagery </li></ul><ul><li>Benefits  </li></ul><ul><li>No restrictions </li></ul><ul><li>...
<ul><li>Satellites </li></ul><ul><li>General comments </li></ul><ul><li>Wide range of sensors with stereo capability  </li...
 
 
 
<ul><li>Comparison  </li></ul>50cm 50 days new Min 100 sq km £0.03k Quickbird 30cm Global archive £0.064k (Hts only) SAR 1...
<ul><li>Summary </li></ul><ul><li>There is an increasing amount of height data for flood modelling. The skill is to select...
<ul><li>Other considerations </li></ul><ul><li>Global warming – 10 - 20cm msl rise last century, estimated 50 cm this cent...
 
<ul><li>Coffee break </li></ul>
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Comparison Of Elevation Collection Technologies

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Comparison Of Elevation Collection Technologies

  1. 1. <ul><li>Flood modelling and management </li></ul><ul><li>Glasgow University </li></ul><ul><li>8 September 2004 </li></ul><ul><li>Paul Shaw - GeoVision </li></ul>
  2. 2. <ul><li>Format for morning session </li></ul><ul><li>9-30 – 10.30 Comparison of modern data collection technologies </li></ul><ul><li>10.30 – 10.45 Coffee </li></ul><ul><li>10.45 – 11.45 Comparison of modern data collection technologies (cont) </li></ul><ul><li>11.45 - 12.00 Coffee </li></ul><ul><li>12.00 – 1.00 Remote sensing for environmental monitoring </li></ul><ul><li>1.00 – 2.00 Lunch </li></ul>
  3. 3. <ul><li>How important are heights in flood modelling? </li></ul>
  4. 4. <ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Aerial Photography </li></ul><ul><li>LIDAR - Light Detection and Ranging </li></ul><ul><li>SAR– Synthetic Aperture Radio Detection and Ranging </li></ul><ul><li>Multi Spectral Satellite Imagery </li></ul>
  5. 5. <ul><li>Comparison of data collection technologies </li></ul><ul><li>For each technology a summary on </li></ul><ul><li>Process of data collection </li></ul><ul><li>Potential sources of error </li></ul><ul><li>Benefits and concerns </li></ul><ul><li>General comments </li></ul>
  6. 6. <ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Aerial Photography </li></ul><ul><li>LIDAR - Light Detection and Ranging </li></ul><ul><li>SAR– Synthetic Aperture Radio Detection and Ranging </li></ul><ul><li>Multi Spectral Satellite Imagery </li></ul>
  7. 7. <ul><li>GPS </li></ul><ul><li>Process </li></ul><ul><li>Use technique called RTK or kinematic </li></ul><ul><li>Requires base station and rover </li></ul><ul><li>Requires radio link </li></ul><ul><li>Software converts to grid and geoid heights </li></ul><ul><li>Collect mapping data (as points, polylines,polygons and attributes) </li></ul><ul><li>May require post-plotting using survey infill techniques </li></ul>
  8. 8. <ul><li>GPS </li></ul><ul><li>Potential sources of error </li></ul><ul><li>Grid transformation and geoid model – Link </li></ul><ul><li>Satellite azimuth, number, quality and spread (measured as DOP’s) - Link </li></ul><ul><li>Radio range </li></ul><ul><li>Base station problems </li></ul>
  9. 9. <ul><li>Benefits </li></ul><ul><li>Accurate to 10mm </li></ul><ul><li>Certainty with ground heights </li></ul><ul><li>Accurate definition of break lines </li></ul><ul><li>Data collected in useable format </li></ul>GPS <ul><li>Concerns </li></ul><ul><li>Slow at 0.2 sq km/day </li></ul><ul><li>Not allowed in all countries </li></ul><ul><li>Radio strength </li></ul><ul><li>Foliage and infrastructure </li></ul><ul><li>No image </li></ul><ul><li>Access restrictions </li></ul>
  10. 10. <ul><li>GPS </li></ul><ul><li>General comments </li></ul><ul><li>Many UK companies - Link </li></ul><ul><li>In GB OS have active and passive stns – Link </li></ul><ul><li>OS trig and BM system redundant </li></ul><ul><li>NAVSTAR (US) – 29 operational at present - Link </li></ul><ul><li>GLONASS (Russian) - 8 operational at present – ( Link ) </li></ul><ul><li>GALILEO (European) – operational from 2008 – 30 in total – ( Link ) </li></ul><ul><li>Started becoming available in the mid nineties </li></ul><ul><li>Further details on how GPS works at ( Link ) </li></ul>
  11. 11. <ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Aerial Photography </li></ul><ul><li>LIDAR - Light Detection and Ranging </li></ul><ul><li>SAR– Synthetic Aperture Radio Detection and Ranging </li></ul><ul><li>Multi Spectral Satellite Imagery </li></ul>
  12. 12. <ul><li>Aerial Photography </li></ul><ul><li>Process </li></ul><ul><li>Route planning; weather forecasting; flying permission; possible pre-mark; control network </li></ul><ul><li>Film processing </li></ul><ul><li>Possible Scanning </li></ul><ul><li>Photo/Imagery control </li></ul><ul><li>Aerial triangulation </li></ul><ul><li>DEM generation; possible vector digitising; post plotting; integration </li></ul><ul><li>Ortho production/mosaicing </li></ul>
  13. 13. <ul><li>Aerial Photography </li></ul><ul><li>Potential sources of error </li></ul><ul><li>Crabbing, fore and aft overlap </li></ul><ul><li>Lens calibration </li></ul><ul><li>Film quality </li></ul><ul><li>Verticality </li></ul><ul><li>Scale problems through large terrain change </li></ul><ul><li>Forward Motion </li></ul><ul><li>Photo control errors </li></ul>
  14. 14. <ul><li>Concerns </li></ul><ul><li>Flying permission required </li></ul><ul><li>Seasonal </li></ul><ul><li>Weather dependency </li></ul><ul><li>Heights to top of foliage </li></ul><ul><li>Restrictions by government </li></ul><ul><li>Matching of orthos </li></ul><ul><li>Automated DEM’s </li></ul>Aerial Photography <ul><li>Benefits </li></ul><ul><li>Large areas covered in one flight </li></ul><ul><li>Height generated from the imagery </li></ul><ul><li>Infrared available </li></ul><ul><li>Orthophotos </li></ul><ul><li>3D visualisations </li></ul><ul><li>Automated DEM’s </li></ul>
  15. 15. <ul><li>Aerial Photography </li></ul><ul><li>General comments </li></ul><ul><li>Was used by the EA – replaced by LIDAR in 1998 </li></ul><ul><li>Increasingly sophisticated on-board systems </li></ul><ul><li>Approx 10 UK companies </li></ul><ul><li>Fixed Wing or helicopter, hard copy or digital </li></ul><ul><li>Large archive at larger scales through BKS, Simmons Aerofilms, OS, OSNI and others </li></ul><ul><li>Getmapping have GB covered at 1:10,000 – Link Imagery £25 per sq km at 1:10,000 scale, heights extra </li></ul>
  16. 16. <ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Aerial Photography </li></ul><ul><li>LIDAR - Light Detection and Ranging </li></ul><ul><li>SAR– Synthetic Aperture Radio Detection and Ranging </li></ul><ul><li>Multi Spectral Satellite Imagery </li></ul>
  17. 17. <ul><li>LIDAR </li></ul>
  18. 18. <ul><li>LIDAR </li></ul><ul><li>Process </li></ul><ul><li>Route planning; weather forecasting; flying permission; control network </li></ul><ul><li>Processing – last reflection </li></ul><ul><li>DEM generation; </li></ul><ul><li>Post survey infill </li></ul><ul><li>Integration </li></ul>
  19. 19. <ul><li>LIDAR </li></ul><ul><li>Potential sources of error include </li></ul><ul><li>GPS and IMU calibration </li></ul><ul><li>IMU and laser head calibration </li></ul><ul><li>Lazer pulse rate </li></ul><ul><li>GPS baseline length </li></ul><ul><li>Level of uncertainty with ground height </li></ul><ul><li>No break line definition </li></ul><ul><li>Details available at ( Link ) </li></ul>
  20. 20. <ul><li>Benefits </li></ul><ul><li>Accurate to 50mm </li></ul><ul><li>Large areas covered in one flight (30 sq km in one hour) </li></ul><ul><li>Can be flown at night </li></ul><ul><li>Not dependent on sun </li></ul><ul><li>Water height </li></ul>LIDAR <ul><li>Concerns </li></ul><ul><li>No image </li></ul><ul><li>Weather dependency </li></ul><ul><li>Flying permission required </li></ul><ul><li>Processing time – up to 4 months for a few days data collection </li></ul>
  21. 21. <ul><li>LIDAR </li></ul><ul><li>General comments </li></ul><ul><li>4 UK companies – global directory at ( Link ) </li></ul><ul><li>QinetiQ have combined with digital cameras to create ATLAS system – ( Link ) </li></ul><ul><li>General information about LIDAR can be found at ( Link and Link ) </li></ul><ul><li>Used extensively by the EA - archive coverage - Link . Catalogue - Link </li></ul>
  22. 23. <ul><li>Coffee break </li></ul>
  23. 24. <ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Aerial Photography </li></ul><ul><li>LIDAR - Light Detection and Ranging </li></ul><ul><li>SAR– Synthetic Aperture Radio Detection and Ranging </li></ul><ul><li>Multi Spectral Satellite Imagery </li></ul>
  24. 25. <ul><li>SAR </li></ul><ul><li>Process (InterMap) </li></ul><ul><li>Aircraft has 2 antennae, receive slightly different return signals, phase difference determines height </li></ul><ul><li>Synthetic aperture digitally enhances the data in real time </li></ul><ul><li>Rigorous QC processing checks </li></ul><ul><li>DEM </li></ul><ul><li>DSM by interpolation </li></ul><ul><li>Intermap SAR description at ( Link ) </li></ul>
  25. 26. <ul><li>SAR </li></ul><ul><li>Potential sources of error </li></ul><ul><li>Shadow </li></ul><ul><li>Rain shadow </li></ul><ul><li>S ignal saturation </li></ul><ul><li>Missing data </li></ul><ul><li>Specular reflection </li></ul><ul><li>DSM generation </li></ul><ul><li>Details at ( Link ) </li></ul>
  26. 27. <ul><li>Benefits </li></ul><ul><li>Can cover 100 sq km in a few hours </li></ul><ul><li>Generates height (up to 0.3m) and image (up to 2.5m) </li></ul><ul><li>All weather capability </li></ul>SAR <ul><li>Concerns </li></ul><ul><li>Flying permission required </li></ul><ul><li>Gives height to first reflection </li></ul><ul><li>Accuracy of DSM </li></ul><ul><li>No break lines - Nextmap products are 5 and 10m grid spacing </li></ul>
  27. 28. <ul><li>SAR </li></ul><ul><li>General comments </li></ul><ul><li>No UK companies </li></ul><ul><li>Accuracy comparison by EA available at ( Link ) </li></ul><ul><li>Nextmap data for UK has 2 accuracy levels – 0.6m for the SE and 1.5m for the rest </li></ul><ul><li>QinetiQ have just gained reseller status </li></ul><ul><li>Nextmap archive at Link </li></ul><ul><li>Intermap global archive and prices at Link </li></ul>
  28. 29. <ul><li>Comparison of data collection technologies </li></ul><ul><li>GPS - Global Positioning Systems </li></ul><ul><li>Aerial Photography </li></ul><ul><li>LIDAR - Light Detection and Ranging </li></ul><ul><li>SAR– Synthetic Aperture Radio Detection and Ranging </li></ul><ul><li>Multi Spectral Satellite Imagery </li></ul>
  29. 30. <ul><li>Multi Spectral Satellites Imagery </li></ul><ul><li>Process </li></ul><ul><li>Order and collect basic imagery </li></ul><ul><li>Image control points </li></ul><ul><li>Rectification </li></ul><ul><li>DEM generation </li></ul><ul><li>Possible vector digitising </li></ul><ul><li>Map completion </li></ul>
  30. 31. <ul><li>Multi Spectral Satellites Imagery </li></ul><ul><li>Potential sources of error </li></ul><ul><li>Cloud </li></ul><ul><li>Other atmospheric interference </li></ul><ul><li>Off-nadir angle of separate image </li></ul><ul><li>Sun </li></ul><ul><li>Shadow </li></ul><ul><li>Incorrect sensor calibration details </li></ul>
  31. 32. <ul><li>Multi Spectral Satellites Imagery </li></ul><ul><li>Benefits </li></ul><ul><li>No restrictions </li></ul><ul><li>Large archives </li></ul><ul><li>Large area coverage </li></ul><ul><li>Repeatability </li></ul><ul><li>Concerns </li></ul><ul><li>Problems with automated DEM’s </li></ul><ul><li>Weather dependency </li></ul><ul><li>Heights to top of foliage/buildings </li></ul><ul><li>Height accuracy still at research stage </li></ul>
  32. 33. <ul><li>Satellites </li></ul><ul><li>General comments </li></ul><ul><li>Wide range of sensors with stereo capability </li></ul><ul><li>On-going program of launch of new satellites </li></ul><ul><li>Quickbird ( Link ), IKONOS ( Link ), SPOT ( Link ), IRS ( Link ). </li></ul><ul><li>Recent research by a Japanese University has shown 0.5m height accuracy possible – Link </li></ul><ul><li>Quickbird archive at Link </li></ul>
  33. 37. <ul><li>Comparison </li></ul>50cm 50 days new Min 100 sq km £0.03k Quickbird 30cm Global archive £0.064k (Hts only) SAR 15cm 120 days new GB archive £0.35k LIDAR (No image) 4cm 50 days new Global archive £3-5k Aerial Photography 1cm 50 days/sq km new £5-10k GPS (No image) Accuracy Delivery Cost/sq km Technology
  34. 38. <ul><li>Summary </li></ul><ul><li>There is an increasing amount of height data for flood modelling. The skill is to select the correct one for a given application. Considerations include:- </li></ul><ul><li>How accurate do you want the heights? </li></ul><ul><li>How regular do you want it monitored? </li></ul><ul><li>What intensity of information do you want? </li></ul><ul><li>How much money have you got? </li></ul><ul><li>How quickly do you want it? </li></ul><ul><li>but................. </li></ul>
  35. 39. <ul><li>Other considerations </li></ul><ul><li>Global warming – 10 - 20cm msl rise last century, estimated 50 cm this century - ( Link ) </li></ul><ul><li>Glacial Isostatic Adjustment – 2 mm per annum (- in South, + in North) – ( Link ). General Info at ( Link ) </li></ul><ul><li>OS recently adjusted UK geoid – up to 10cm variance </li></ul><ul><li>Spring tides – up to 12m range - ( Link and Link ) </li></ul><ul><li>Tidal loading – up to 6cm variance in 1 day </li></ul>
  36. 41. <ul><li>Coffee break </li></ul>
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