Keywords: Spatial statistics, spherical geometry, geospatial index, GIS
Webpages:
https://github.com/spatstat/s2,
https://cran.r-project.org/package=s2 Google’s S2 geometry library is a somewhat hidden gem which hasn’t received the attention it deserves. It both facilitates geometric operations directly on the sphere such as polygonal unions, intersections, differences etc. without the hassle of projecting data in the common latitude and longitude format, and provides an efficient quadtree type hierarchical geospatial index.
The original
C++ source code is available in a
Google Code archive and it has been partially ported to e.g. Java, Python, NodeJS, and Go, and it is used in MongoDB’s 2dsphere index.
The geospatial index in the S2 library allows for useful approximations of arbitrary regions on the sphere which can be efficiently manipulated.
We describe how the geospatial index is constructed and some of it properties as well as how to perform some of the geometrical operations supported by the library. This is all done using
Rcpp to interface the
C++ code from
R.
