Developing an Equal Area Global Grid by Small Circle Subdivision

Abstract

Modern environmental monitoring and modeling requires partitioning the earth's surface into a global grid optimized for survey sampling and unbiased, spatially complete data collection of relevant environmental phenomena. Prime requirements are that cells comprising the grid be equal in area, regular in shape, and highly compact on the earth's ellipsoidal surface. No existing global grid fully meets these criteria. We propose a new equal area global partitioning method based upon small circle edges on the earth's surface, which we call the "small circle subdivision method." A detailed description of this method is presented, including its mathematical derivation and geometrical comparison with alternative methods. The small circle method appears to be the best developed to date to satisfy the essential criteria for a global grid.