Short Course: Introduction to Geomorphic Change Detection

In an era of abundant high-resolution topographic survey data and acquisition methods (RTK-GPS, LiDAR and Structure-from-Motion), it is becoming increasingly important to understand and master new workflows for assessing the quality of digital elevation models (DEMs), the extents of 2D and 3D change, and the variance and error in DEMs of difference.

The freely available GCD software suite was developed to streamline the process of evaluating topographic change within a time series of survey data, which is applicable in a range of environments. 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 differentiating the changes between the surveys that are due to geomorphic change from the changes due to noise in the DEMs. 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.