The GCD software was developed primarily for morphological sediment budgeting in rivers. The volumetric change in storage is calculated from the difference in surface elevations from digital elevation models (DEMs) derived from repeat topographic surveys. As each DEM has an uncertain surface representation (which might vary in space and time), our ability to detect changes between surveys is highly dependent on surface representation uncertainties inherent in the individual DEMs. The fundamental problem is separating out the changes between the surveys that are due to geomorphic change as opposed to noise in the survey data. GCD provides a suite of tools for quantifying those uncertainties independently in each DEM and propagating them through to the DEM of difference. The program also provides ways for segregating the best estimates of change spatially using different types of masks. The overall suite of tools is more generically applicable to many different spatial raster-based change detection problems.
DEM error modelling, change detection, DEM uncertainty, geomorphic interpretation
Wheaton JM, Brasington J, Darby SE and Sear D. 2010. Accounting for Uncertainty in DEMs from Repeat Topographic Surveys: Improved Sediment Budgets. Earth Surface Processes and Landforms. 35 (2): 136-156. DOI: 10.1002/esp.1886