In geography , the centroid of the two-dimensional shape of a region of the Earth's surface (projected radially to sea level or onto a geoid surface) is known as its geographic centre or geographical centre or (less commonly) gravitational centre . Informally, determining the centroid is often described as finding the point upon which the shape (cut from a uniform plane) would balance. This method is also sometimes described as the "gravitational method".
6-439: One example of a refined approach using an azimuthal equidistant projection, also potentially incorporating an iterative process, was described by Peter A. Rogerson in 2015. The abstract says "the new method minimizes the sum of squared great circle distances from all points in the region to the center". However, as that property is also true of a centroid (of area), this aspect is effectively just different terminology for determining
12-559: Is no generally accepted definition of geographic center, and no completely satisfactory method for determining it." In general, there is room for debate around various details such as whether or not to include islands and similarly, large bodies of water, how best to handle the curvature of the Earth (a more significant factor with larger regions) and closely related to that issue, which map projection to use. GNS Science GNS Science ( Māori : Te Pū Ao ), officially registered as
18-463: The Institute of Geological and Nuclear Sciences Limited , is a New Zealand Crown Research Institute . It focuses on geology , geophysics (including seismology and volcanology ), and nuclear science (particularly ion-beam technologies , isotope science and carbon dating ). As well as undertaking basic research, and operating the national geological hazards monitoring network ( GeoNet ) and
24-641: The National Isotope Centre (NIC), GNS Science contracts its services to various private groups (notably energy companies) both in New Zealand and overseas, as well as to central and local government agencies, to provide scientific advice and information. GNS Science has its head office in Avalon , Lower Hutt , with other facilities in Gracefield , Dunedin , Wairakei , Auckland and Tokyo . GNS Science
30-406: The centroid. In 2019, New Zealand's GNS Science also used an iterative approach (and a variety of different projections) when determining a centre position for New Zealand's Extended Continental Shelf . However, other methods have also been proposed or used to determine the centres of various countries and regions. These include: As noted in a United States Geological Survey document, "There
36-605: Was known as the Institute of Geological and Nuclear Sciences (IGNS) from 1992 to 2005. Originally part of the New Zealand Government's Department of Scientific and Industrial Research (DSIR), it was established as an independent organisation when the Crown Research Institutes were set up in 1992. In late September 2024, GNS Science confirmed that 59 roles would be cut, amounting to ten percent of its workforce. In addition, 37 new roles would be created. This
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