1. Aberdeen Institute for Coastal Science and Management, University of Aberdeen Team (alphabetical order): Alastair Dawson Cristina Gomez David Green William Ritchie Amy Taylor Robert Wright TERRAIN MODELLING FOR THE ASSESSMENT OF COASTAL CHANGE Society of Cartographers Annual Summer Conference 2008 (1st September)

2. Overview Society of Cartographers Annual Summer Conference 2008 (1st September) Background Objective Location of study sites Data used Methodology Results Visualization: DTM, photo mosaics Analysis and interpretation: Visual interpretation of geomorphology Planimmetric change Volumetric change

3. BACKGROUND OBJECTIVE Coastal environment importance: dunes and coast line. Lack of data of the causes and rate of change in Scotlands natural heritage. Evidence of morphology change. Study recent (last decades) changes in beach and dune systems in Scotland Work done for the project: Assessment of the rates and causes of change in Scotlands beaches and dunes (AICSM for SNH) Society of Cartographers Annual Summer Conference 2008 (1st September)

4. SITES LOCATION Selection criteria: Out of human excessive influence Areas of submergence and emergence (postglacial) Availability of aerial photography: two different dates metric (useful for analytical photogrammetry) Society of Cartographers Annual Summer Conference 2008 (1st September)

5. DATA Aerial photography: stereo pairs to create the DEM (Digital Elevation Model)-DTM GCP (Ground Control Points): for photography orientation and aero triangulation For reference and comparison: Ancillary maps: OS 1800s coast lines for comparison Recent maps: OS digital recent maps Society of Cartographers Annual Summer Conference 2008 (1st September)

6. METHODOLOGY Interior orientation Import frames Triangulation Mosaic imagesDTM creation Edition Aerial photos Ground Control Points Photogrammetry (Socetset) ASCII to raster Raster algebraSurface analysisSpatial analysisVisual analysis Change mapContoursVolumeFlythrough GIS (ArcGis) Export to ASCII Society of Cartographers Annual Summer Conference 2008 (1st September)

7. DTM creation Overlapping 60 % end lap 30 % lateral Society of Cartographers Annual Summer Conference 2008 (1st September) Import frames: Stereo pairs Complexity Big areas - many stereo pairs Ground Control Points Tie points Triangulation

8. Society of Cartographers Annual Summer Conference 2008 (1st September) DTM resolution (size of raster cell) Small enough to capture the variability of the terrain Big areas-----big files 2-5 m Important to compare DTMs Finer resolution tested– disturbances, spikes Sources of error Photos GCP: 0.1 m------ but good distribution??? Algorithms for triangulation and DTM creation Accuracy--- Better than 0.5 m DTM creation

9. Product: Digital Elevation Model Sands of Forvie 2001Sands of Forvie 1967 Results Society of Cartographers Annual Summer Conference 2008 (1st September)

10. Traditional visualization of height map Results Society of Cartographers Annual Summer Conference 2008 (1st September)

11. Detail of DEM, raster Detail of DEM, contour 3D visualization of height map DTM: Visualization Society of Cartographers Annual Summer Conference 2008 (1st September)

12. Photo draped on DEM Society of Cartographers Annual Summer Conference 2008 (1st September) DTM: Visualization Lucebay parallel dunes Sands of Forvie south dune in 1984 with key contour lines

13. Photo Mosaics Visualization Society of Cartographers Annual Summer Conference 2008 (1st September) Morrichmore in 2005

14. Analysis and interpretation Planimmetric change: mapping and comparing lines for different dates vegetation boundary line zero meter Above Ordnance Datum (0 m line) HWMOST (high water mark ordinal spring tide) Volumetric change: raster algebra with pairs of DTM for comparison Visual interpretation of DTMs geomorphology Society of Cartographers Annual Summer Conference 2008 (1st September)

15. Visualization Society of Cartographers Annual Summer Conference 2008 (1st September) Sandwood Bay in 2004

16. Analysis: planimmetric change Society of Cartographers Annual Summer Conference 2008 (1st September) Culbin Sands

17. Analysis: planimmetric change Society of Cartographers Annual Summer Conference 2008 (1st September)

18. Analysis: planimmetric change Society of Cartographers Annual Summer Conference 2008 (1st September)

19. Analysis: planimmetric change

20. Planimetric changes: zero m AOD line Society of Cartographers Annual Summer Conference 2008 (1st September)

21. Volume change calculation: raster algebra Analysis: volumetric change Society of Cartographers Annual Summer Conference 2008 (1st September)

22. Analysis: Volumetric change Morrichmore map of height change 1967-2005 Society of Cartographers Annual Summer Conference 2008 (1st September) 2D 3D

23. Visualization of volumetric changes Society of Cartographers Annual Summer Conference 2008 (1st September) Scheme of colours: red: erosion white: no change green: accretion Analysis: Volumetric change Flythroughs

24. Society of Cartographers Annual Summer Conference 2008 (1st September) Location of areas with major change Evaluation of change: erosion accretion Interpretation of change, causes: climate others Temporal/Permanent Analysis and Interpretation

25. Contrast with former studies or theories Confirmation of hypothesis Society of Cartographers Annual Summer Conference 2008 (1st September)

26. Profiles for interpretation Society of Cartographers Annual Summer Conference 2008 (1st September) Analysis and Interpretation

27. Methodology conclusions Coastal environments present special problems in creation of DTM: Waves Permanent water Applicability is conditioned by: Photography: availability, date, quality Field quality data: GCP Sources of error: data, algorithms. Results have to be carefully interpreted and used Society of Cartographers Annual Summer Conference 2008 (1st September)

28. Main findings of the project Scotlands beaches and dunes are dynamic features and subject to rapid but variable rates of change. Some coastlines are advancing, some retreating. The main factor affecting the change appears to be sediment availability and recycling. The most recent tide data points to a typical rise in relative sea across Scotland over the last 150 years of around 30 centimeters. The geomorphological effects on Scotlands beaches and dunes of storminess history may be much more important but there is no firm evidence to link this to any long-term rise in relative sea level or any other aspect of climate change. Society of Cartographers Annual Summer Conference 2008 (1st September)

29. Thanks for your attention Society of Cartographers Annual Summer Conference 2008 (1st September)