Development and User Testing of a Python Interface to the GRAVSOFT Gravity Field Programs

The GRAVSOFT suite of Fortran programs enables gravity field modeling using 3D or 2D Least-Squares Collocation and Fourier techniques, the computation of topographic effects, the evaluation of high-degree spherical harmonic series and several other functions. It has been developed since the early 1970s with a line-oriented DOS-interface. Sponsored by the Geodetic Survey of Malaysia a modern graphical interface has been designed using Python (www.python.org) and the widget toolkit Tk, following the Apple Design Guidelines. A prototype was designed and tested at a geoid workshop in Malaysia. An iteration of this was then tested at the International Geoid School, Como and a third iteration during a graduate course at the University of Copenhagen. The result is two main redesigns; the GRAVSOFT Launcher Interface and the brows-ing Interface. User evaluation showed high satisfaction with the Interface, but identified the error/help support as dissatisfying. However 1 in 4 found it difficult to learn to use the programs. Difficulties in learning is correlated with participants educational level, showing that when applications – which have been used in research – target other user groups, redesign and user testing is required