tectonicr is a free and opensource R package for modeling and analyzing the direction of the maximum horizontal stress (SHmax) based on the empirical link between the direction of intraplate stress and the direction of the relative motion of neighboring plates. The following methods are available:

Theoretical direction of SHmax: The predicted stress field adjacent to a plate boundary is calculated using the relative plate motion of the neighboring plates using the function
model_shmax()
. The deviation or misfit of the prediction to the observation can be obtained from the functionmisfit_shmax()
and statistically evaluated by applyingnorm_chisq()
. 
Distance to plate boundary:
distance_from_pb()
gives the distance between the stress data point and the plate boundary measured along the stress trajectories. 
Visualization of the trajectories of the theoretical stress field in terms of small circles, great circles, and lines of constant bearing. The
eulerpole_paths()
functions generates ansf
object containing spatial information that is suitable to plot with, for instance,ggplot()
. 
Relative rotations from a given set of plate motion parameters:
equivalent_rotation()
transfers a set of plate motion parameters into the relative plate motions among the given plates.  Average direction of a set of SHmax data using the (weighted) mean or median for pidirectional data.

Spatial interpolation of of SHmax:
stress2grid()
uses distance, method, and qualityweighted mean direction of stress data
Prerequisites
You must have R installed on your system (see http://rproject.org). To install tectonicr from Github, you also need the remotes
package. This can be installed by typing the following code at the R command line prompt:
install.packages("remotes")
Installation
The most recent development version of tectonicr is available from Github and can be installed on your system as follows:
remotes::install_github('tobiste/tectonicr')
library('tectonicr')
How to cite
When referencing this package, please cite the package DOI: 10.5281/zenodo.7042082.
Useful References
 Wdowinski, S. (1998). A theory of intraplate tectonics. Journal of Geophysical Research: Solid Earth, 103(3), 5037–5059. http://dx.doi.org/10.1029/97JB03390
 Heidbach, O., Reinecker, J., Tingay, M., Müller, B., Sperner, B., Fuchs, K., & Wenzel, F. (2007). Plate boundary forces are not enough: Second and thirdorder stress patterns highlighted in the World Stress Map database. Tectonics, 26(6), n/an/a. https://doi.org/10.1029/2007TC002133
 Heidbach, O., Rajabi, M., Reiter, K., Ziegler, M., & Team, W. (2016). World Stress Map Database Release 2016. V. 1.1. GFZ Data Services. https://doi.org/10.5880/WSM.2016.001
 Zoback, M. Lou, Zoback, M. D., Adams, J., Assumpção, M., Bell, S., Bergman, E. A., Blümling, P., Brereton, N. R., Denham, D., Ding, J., Fuchs, K., Gay, N., Gregersen, S., Gupta, H. K., Gvishiani, A., Jacob, K., Klein, R., Knoll, P., Magee, M., … Zhizhin, M. (1989). Global patterns of tectonic stress. Nature, 341(6240), 291–298. https://doi.org/10.1038/341291a0