Spherical Rectangular Equal-Area Grid (SREAG): Some features

TL;DR

The paper details the features and capabilities of the Spherical Rectangular Equal-Area Grid (SREAG), including its maximum resolution, computational precision, and formulas for grid configuration.

Contribution

It provides an in-depth analysis of SREAG's features, including maximum resolution, precision, and practical formulas for grid setup.

Findings

Maximum resolution of ~16 arcseconds with 32-bit coding.

Computational precision up to 7×10^{-12}.

Derived formulas for grid configuration and resolution.

Abstract

A new method Spherical Rectangular Equal-Area Grid (SREAG) was proposed in Malkin (2019) for splitting spherical surface into equal-area rectangular cells. In this work, some more detailed features of SREAG are presented. The maximum number of rings that can be achieved with SREAG for coding with 32-bit integer is $N_{ring}$=41068, which corresponds to the finest resolution of $\sim$16$''$. Computational precision of the SREAG is tested. The worst level of precision is $7\cdot10^{-12}$ for large $N_{ring}$. Simple expressions were derived to calculate the number of rings for the desired number of cells and for the required resolution.