Spherical Data Handling and Analysis with R package rcosmo

Abstract

The R package rcosmo was developed for handling and analysing Hierarchical Equal Area isoLatitude Pixelation(HEALPix) and Cosmic Microwave Background(CMB) radiation data. It has more than 100 functions. rcosmo was initially developed for CMB, but also can be used for other spherical data. This paper discusses transformations into rcosmo formats and handling of three types of non-CMB data: continuous geographic, point pattern and star-shaped. For each type of data we provide a brief description of the corresponding statistical model, data example and ready-to-use R code. Some statistical functionality of rcosmo is demonstrated for the example data converted into the HEALPix format. The paper can serve as the first practical guideline to transforming data into the HEALPix format and statistical analysis with rcosmo for geo-statisticians, GIS and R users and researches dealing with spherical data in non-HEALPix formats.

rcosmo: R Package for Analysis of Spherical, HEALPix and Cosmological Data

“…> worldcities <-read.csv("worldcities.csv") > sph <-geo2sph(data.frame(lon = pi/180*worldcities$lng, lat = pi/180*worldcities$lat)) > df1 <-data.frame(phi = sph$phi, theta = sph$theta, I = rep(1,nrow(sph))) > hp <-HPDataFrame(df1, auto.spix = TRUE, nside = 1024) > plot(hp, size = 3, col = "darkgreen", back.col = "white") Some other examples of converting directional and star-shaped data into rcosmo formats are given in (Fryer and Olenko, 2019).…”