{structr} is a free and open-source package for R that provides tools for structural geology. You can

• analyze and visualize orientation data of structural geology (including, stereographic projections, contouring, fabric plots, and statistics),

• do a cluster analysis of orientation data,

• analyze stress (including visualization of the magnitudes of stress in the Mohr circle and extracting the maximum horizontal stress of a 3D stress tensor),

• reconstruct the orientation of structures in oriented drillcores by transforming the α, β, and γ angles,

• calculate fault displacement components,

• reconstruct orientation and magnitudes using fault-slip inversion (Paleostress analysis),

• strain analysis (R_f/ϕ), contouring on the unit hyperboloid, Fry plots and Hsu plots

• perform vorticity analysis using the Rigid Grain Net method, and

• directly import your field data from StraboSpot.

The {structr} package is all about structures in 3D. For analyzing orientations in 2D (statistics, rose diagrams, etc.), check out the tectonicr package!

You can install the development version of {structr} from GitHub with:

# install.packages("devtools")
devtools::install_github("tobiste/structr")

This is a basic example which shows you how to import data and plot them on stereographic or equal-area projections.

library(structr)
library(ggplot2)
library(mapproj)

data(example_planes)
planes <- Plane(example_planes$dipdir, example_planes$dip)

fabric <- or_shape_params(planes)$Vollmer["D"]

ggstereo() +
  geom_contourf_stereo(gg(planes)) +
  geom_point(data = gg(planes), aes(x, y), color = "grey", shape = 21) +
  scale_fill_viridis_d(option = "F") +
  labs(
    subtitle = "Example data",
    title = "Density contour plot",
    fill = "Multiples of\nvon Mises-Fisher\ndistribution",
    caption = paste0("Equal area, lower hemisphere projection | N: ", nrow(planes), " | Fabric strength: ", round(fabric, 2))
  )

The detailed documentation can be found at https://tobiste.github.io/structr/

Tobias Stephan (tstephan@lakeheadu.ca)

I welcome feedback, suggestions, issues, and contributions! If you have found a bug, please file it here with minimal code to reproduce the issue.

MIT License