soapcheckr

Check whether a soap film smoother boundary and knots make sense

Setting up a soap film smoother is often a hard and frustrating process. This packages provides functions that checks the boundary, knots, and data that you feed to a soap are “correct”. The functions in the package will also plot the area that will be modeled by the soap film smoother in red, and knots and/or data as circles as viable locations. Any circles that have a X through them are considered inadequate and will need to be removed.

To do the spatial analysis, we require a couple of extra libraries: {sf} and {mgcv}. That will be loaded when installing {soapcheckr}.

{soapcheckr} can be installed using the following code;

install.packages("devtools")
devtools::install_github("dill/soapcheckr")

Next load {soapcheckr} and walk through the vignette to see how to use the functions. We highly encourage walking through both examples in the vignette.

library(soapcheckr)
vignette("how_to_use_soapcheckr")

Other tips

• Note that you need to set the k and nmax argument in autocruncher() to be the same as your planned value in gam() for your soap film smoother
• The functions assumes that your spatial variable names are x and y unless you supply the naming arguments with the column names from your data.
• Make sure that your locations are in Northings/Eastings, (e.g., UTMs). Using latitude and longitude (e.g., decimal degree) will give strange results (as the soap film smoother is isotropic so treats 1 unit change in either dimension is equal, this isn’t true for lat/long!).
• Sometimes you need to increase the tolerance (e.g tol = 1e-6) argument when using soap_check()
• Note that the boundary must be a list of lists or data.frames. So if you have a polygon boundary with your boundary vertices in it, that must be wrapped in a list! The vector names of each boundary need to be names x and y for the functions to work.
• You can also access the vignette at the following blog post

Written by David L. Miller and Benjamin L. Hlina. Released under the GPL (version 2).