SSPX is a program to calculate strain/strain rate from displacement/velocity data in two and three dimensions. SSPX is a full fledged inverse modeling program to calculate best fitting deformation tensors given displacement or velocity vectors at a minimum of three points in two dimensions, or four points in three dimensions.
SSPX works equally well on small deformation problems such as computing strain rates from Global Positioning System (GPS) data, and large deformation problems such as computing the strain in a highly deformed discrete element model (DEM). SSPX was made for geologists, but it can be used by anyone interested in computing strain/strain rate from displacement/velocity data.
SSPX is based on StrainSimPro, a program by Richard Allmendinger to compute strain rates from GPS data. SSPX is freeware for non-profit, academic purposes. To use the program for consulting, please contact Nestor Cardozo at nfcd [at] mac.com or Richard Allmendinger at rwa1 [at] cornell.edu.
What’s new in this version:
Version 1.7:
- Add a menu to compute strain at stations
- Allow Plot -> principal and rotation axes menus to toggle on/off axes in stereonet
- Fix several bugs for surfaces following the topography of the stations. Now this only has effects on Nearest Neighbor computations, where elevation of any point on surface is equal to average elevation of neighbors. Otherwise, surface is horizontal and with the datum specified in the Inspector.
- Scale plot using a ratio in Scale Limits panel
- Dot in red close button indicates unsaved/dirty document
- Inspector and Color Bar panels float on top of document
- Put Color Bar menu under View menu
- Fix bug in Delaunay computation
- Fix bug when writing 3D as 2D strain to text files
- Fix bug when saving 3D as 2D strain to kml files
- Fix minor interface glitches
