This algorithm calculates height differences between elevation pairs within a user-defined search radius. Suggested values are between 50 and 500-1 000 m, depending on the desired output resolution and on the slope and roughness of the topographic surfaces. The user can choose to output results only within a predefined range of the elevation differences, e.g., all pairs with height differences between 0.5 m and 5 m. More details are in Alberti & Biscaro (2010).
Language: Fortran 90/95
Compiler: g95 - Windows
Since data in GLA12 files are in big-endian notation (the Unix default), compile the program in Windows using the big-endian data option.
For example, with the free g95 compiler, the command line should include the "-fendian=BIG" option, e.g.:
prompt> g95 HeightVarGLA_v1.0.f95 -fendian=BIG -o heightvar.exe
The input for the elaborations consists of one or two binary files (with .dat extension) created by the ReadGLA12 program, storing data for a specific geographic domain acquired in a single time interval (when using one input file) or in two different time intervals (two input files).
Filtered-in pairs are written in an output text file that can be easily imported into GIS software. A metadata file stores information about the analysis session and analysed tracks (e.g., time, input files, used thresholds on distance and elevation differences, and summary results for each track).