sphunif (version 1.4.3)

craters: Craters named by the IAU

Description

Named craters of the Solar System by the Gazetteer of Planetary Nomenclature of the International Astronomical Union (IAU).

Usage

craters

Format

A data frame with 5235 rows and 7 variables:

ID

database ID.

name

name of the crater.

target

name of the celestial body. A factor with 43 levels, such as "Moon", "Venus", or "Europa".

target_type

type of celestial body. A factor with 3 levels: "Planet", "Moon", "Dwarf planet", or "Asteroid".

diameter

diameter of the crater (in km).

theta

longitude angle \(\theta \in [0, 2\pi)\) of the crater center.

phi

latitude angle \(\phi \in [-\pi/2, \pi/2]\) of the crater center.

Details

"Craters" are understood in the Gazetteer of Planetary Nomenclature as roughly circular depressions resulting from impact or volcanic activity (the geological origin is unspecified).

Be aware that the dataset contains only named craters by the IAU. Therefore, a uniform bias is likely present on the distribution of craters. Presumably the naming process attempts to cover the planet in a somehow uniform fashion (distant craters are more likely to be named than neighboring craters). Also, there are substantially more craters in the listed bodies than those named by the IAU. See venus and rhea for more detailed and specific crater datasets.

The \((\theta, \phi)\) angles are such the associated planetocentric coordinates are: $$(\cos(\phi) \cos(\theta), \cos(\phi) \sin(\theta), \sin(\phi))',$$ with \((0, 0, 1)'\) denoting the north pole.

The script performing the data preprocessing is available at craters.R. The data was retrieved on 2020-05-31.

Examples

# Load data
data("craters")

# Add Cartesian coordinates
craters$X <- cbind(cos(craters$theta) * cos(craters$phi),
                   sin(craters$theta) * cos(craters$phi),
                   sin(craters$phi))

# Tests to be performed
type_tests <- c("PCvM", "PAD", "PRt")

# Tests for Venus and Rhea
unif_test(data = craters$X[craters$target == "Venus", ], type = type_tests,
          p_value = "asymp")
unif_test(data = craters$X[craters$target == "Rhea", ], type = type_tests,
          p_value = "asymp")