README.md
In geoprofiler: Perpendicular Line Transects for Geosciences

geoprofiler

The goal of {geoprofiler} is to get distances along and across user-defined profile lines or transects. This is useful to visualize the distance-dependency of some variables in the geosciences.

The concept of {geoprofiler} is a coordinate transformation of your geo-coordinates into “profile coordinates”. These coordinates are the distances along and across your profile.

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

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

This is a basic example which shows you how to create a profile.

library(geoprofiler)
library(ggplot2)
#> Warning: package 'ggplot2' was built under R version 4.3.3

Import example data and transfer them into a sf object:

data(quakes)
quakes_sf <- sf::st_as_sf(quakes, coords = c("long", "lat"), crs = "WGS84")

Create a profile line from two known points:

profile <- data.frame(lon = c(160, -170), lat = c(-15, -30)) |>
  sf::st_as_sf(coords = c("lon", "lat"), crs = "WGS84") |>
  sf::st_shift_longitude() |>
  profile_line()

Note: You can also create a profile line by a direction via profile_points()

Calculate the distances of all points along and across the profile line:

quakes_profile <- profile_coords(quakes_sf, profile = profile) |>
  dplyr::bind_cols(quakes_sf)

Finally, create your profile plot:

ggplot(quakes_profile, aes(X, depth, color = mag, size = abs(Y), alpha = abs(Y))) +
  geom_point() +
  scale_color_viridis_c("Richter magnitude", option = "A") +
  scale_size_continuous(bquote("Distance from profile (" * degree * ")"), range = c(3, .1)) +
  scale_alpha_continuous(bquote("Distance from profile (" * degree * ")"), range = c(1, .1)) +
  scale_y_reverse() +
  scale_x_continuous(guide = guide_axis(position = "top")) +
  labs(x = bquote("Distance along profile (" * degree * ")"), y = "Depth (km)") +
  theme_classic()

The above example uses the quakes dataset giving the locations of 1000 seismic events of MB > 4.0. The events occurred in a cube near Fiji since 1964.

The detailed documentation can be found at https://tobiste.github.io/geoprofiler/articles/geoprofiler.html

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.

GPL-3.0 License