The sabre (Spatial Association Between REgionalizations) is an R package for calculating a degree of spatial association between regionalizations or categorical maps. This package offers support for sf spatial objects, and the following methods:

  • the V-measure method (Nowosad and Stepinski, 2018)
  • the MapCurve method (Hargrove et al., 2006)

Installation

You can install the released version of sabre from CRAN with:

You can install the development version from GitHub with:

Example

We use two simple regionalization, regions1 and regions2 to show the basic concept of calculating a degree of spatial association.

The first map, regions1 consists of four regions of the same shape and size, while the second one, regions2 has three irregular regions.

The vmeasure_calc() function allows for calculation of a degree of spatial association between regionalizations or categorical maps using the information-theoretical V-measure. It requires, at least, four arguments:

  • x - an sf object containing the first regionalization
  • x_name - a name of the column with regions names of the first regionalization
  • y - an sf object containing the second regionalization
  • y_name - a name of the column with regions names of the second regionalization
regions_vm = vmeasure_calc(regions1, z, regions2, z)

The result is a list with three metrics of spatial association - V-measure, Homogeneity, Completeness - and two sf objects with preprocessed input maps - $map1 and $map2.

Both spatial outputs have two columns. The first one contains regions’ names/values and the second one (rih) describes regions’ inhomogeneities.

plot(regions_vm$map1["rih"], main = "Map1: rih")
plot(regions_vm$map2["rih"], main = "Map2: rih")

More examples can be found in the package vignette.

Additionally, examples presented in the Spatial association between regionalizations using the information-theoretical V-measure article could be reproduced using data available at http://sil.uc.edu/cms/index.php?id=data-1#vmeasure.

References

  • Nowosad, Jakub, and Tomasz F. Stepinski. “Spatial association between regionalizations using the information-theoretical V-measure.” International Journal of Geographical Information Science (2018). https://doi.org/10.1080/13658816.2018.1511794
  • Rosenberg, Andrew, and Julia Hirschberg. “V-measure: A conditional entropy-based external cluster evaluation measure.” Proceedings of the 2007 joint conference on empirical methods in natural language processing and computational natural language learning (EMNLP-CoNLL). 2007.
  • Hargrove, William W., Forrest M. Hoffman, and Paul F. Hessburg. “Mapcurves: a quantitative method for comparing categorical maps.” Journal of Geographical Systems 8.2 (2006): 187.