Stereonet Mobile vs StraboTools

Stereonet Mobile is designed to help you collect, visualize, and analyze geological orientation data. It is a companion to my Stereonet program for desktop computers. As such I have tried to incorporate the basic functionality of that program, taking into account the inherent limitations of mobile devices. Some of the basic tasks that one can perform with Stereonet Mobile include: • Provide automatic data entry as a geologist's compass by reading the iOS device orientation and converting it to strike and dip of planes and/or trend and plunge of lines. It is the only geology compass app that can use augmented reality to record the strike and dip of planes using the sighting method and the device camera. • Provide manual data entry via either tapping and dragging on the stereonet or by typing values into text fields • Plot lines and planes, which can be tagged using one of as many user defined data types (e.g., bedding, cleavage, slickensides, etc.) as you want • Carry out basic calculations such as: rotations about any axis, planes from poles or poles from planes, measure angles between lines and between planes, and basic slope stability calculations • Plot mean vectors, cylindrical best fits, rose diagrams, and contour lines. • View the plots from any orientation, not just looking straight down into the lower hemisphere • See the location of a datum on a map or satellite image (if you have an internet connection) • Show realtime changes to the stereonet projection to help students understand the geometry of the device better • Provide basic input and output of data using standard iOS conventions • Works on iPhones or iPads. The program will work on iPods or iPads lacking a cellular data connection but those devices have fewer sensors and thus cannot be used in automatic data collection mode.

StraboTools is designed to aid geologic field work by providing quantitative data that are otherwise difficult to estimate in the field. The app was developed for work in plutonic rocks such as granite, but it can be useful in field work in any type of rock and for study of thin sections as well. The app analyzes a photograph taken within the app or imported into it. •The Edge Fabric tool plots an ellipse that summarizes the orientations of image brightness gradients. In rocks with a fabric produced by deformation, this ellipse provides the orientation of the fabric and an axial ratio, which correlates with bulk deformation. The tool also reports the orientation in space of the line defined by the long axis of the ellipse. If, for example, the fabric being measured is planar, then these intersection lineations will lie on a great circle. Edge fabric diagrams are useful both in the field and for analysis of photomicrographs. •The Color Index tool allows quantitative determination of the color index (CI; area percent dark minerals) from a photograph. The user takes a photograph and then moves a slider to highlight those pixels darker than a certain threshold. The resulting area percent is displayed. Both adaptive and full-image thresholding are available. •Edge Detect applies an edge detection filter to the image. This can be useful in highlighting subtle features in an outcrop and in interpreting edge fabric ellipses.