1. Topographic Difference Models
Mark Wiggins

2. Overview
Introduction.
Process.
Advantages.
Examples.
Summary.

3. Introduction Tool for measuring overall beach change.
Comparing baseline surveys.
Highlight erosion, accretion and stability.

4. Process Beach Elevation Data (x,y,z).
Two different dates (e.g and 2012).

6. Process Beach Elevation Data (x,y,z).
Two different dates (e.g and 2012).
Create raster images.

8. Process Beach Elevation Data (x,y,z).
Two different dates (e.g and 2012).
Create raster images.
Find common area.

10. Process Beach Elevation Data (x,y,z).
Two different dates (e.g and 2012).
Create raster images.
Find common area.
Subtract rasters.

12. Process Beach Elevation Data (x,y,z).
Two different dates (e.g and 2012).
Create raster images.
Find common area.
Subtract rasters.
Add symbology.

15. Advantages High resolution overview.
Surface volumes (above Mean Low Water Springs).

16. Volume Difference 2007 to 2012: +5,732m3.
Change of +4.3% in material gained.

17. Advantages High resolution overview.
Surface volumes (above Mean Low Water Springs).
Isolate interest areas.

20. Advantages High resolution overview.
Surface volumes (above Mean Low Water Springs).
Isolate interest areas.
Track important features (Dunes, Rivers etc.)

23. Advantages High resolution overview.
Surface volumes (above Mean Low Water Springs).
Isolate interest areas.
Track important features (Dunes, Rivers etc.)
LIDAR, Bathymetric or Topographic data sets.

25. Summary Detailed comparison of baseline data.
Any x,y,z data can be used (Topo, LIDAR, Bathy).
Quantitative analysis of surface volumes.
Isolate dynamic areas/features.