NCSU Open Source Geospatial Research and Education Laboratory
Center for Geospatial Analytics and
Department of Marine, Earth and Atmospheric Sciences
North Carolina State University
Hardin, E., Mitasova, H., Tateosian, L., Overton, M., 2014, GIS-based Analysis of Coastal Lidar Time-Series, Springer Briefs in Computer Science, Springer, New York, 84 p.
Horizontal migration is often associated with change in landform geometry which is hard to measure with standard transects
Sand dune on NC coast: Jockey's Ridge 1974 - 2012
Jockey's Ridge dune horizontal migration: extracting crests and manually measuring distances along transect, to derive spatially agreggated rates
We use the concept of Space-Time Cube where for any contour z=const we can define a function t=g(x,y) where t is the time when this contour is located at the point (x,y). For g(x,y) to be a function, we need to segment time series of contours into non-intersecting segments. Then rate of migration is inverse of the gradient magnitude of the function g(x,y).
Set of 110m contours including the ones derived from core and envelope
Envelope: max elevation at each cell (green), Core: min elevation (red)
Mask external areas outside the range of 110m contour migration
Mask internal areas outside the range of 110m contour migration
Each 110m contour is assigned a time [year] attribute
Temporal surface is interpolated from a time series of 110m contours
Derived from spatio-temporal surface using derivatives of spline function
gradient lines over time and vectors over migration rates
Shows spatial pattern of mass concentration and dispersal over time
Inspired by Tokyo Wind Speed application by Cameron Beccario.
air.js source code.
Gradient field of horizontal migration at z=12m for Jockey's Ridge dune for years 1974, 1995, 2001, 2008, 2012, contour segmentation is needed
Migration of windward side of Jockey's Ridge dune at different elevations
Fire isochrones (time series of burned area polygons) and simulation
Fire spread rate and direction and acceleration
(curvature in the direction of gradient)
This project was funded by the US Army Research Office, grant W911NF1110146.
Everything in the presentation including the presentation itself was created using free, libre and open source software tools.