Talk:Geographic center of the United States

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Problematic

This article should, but does not, describe the methodology used to determine the center. It does explain that a projection (cardboard cut-out) was used for determination of the contiguous center. Also, it is problematic to describe it as the "center of mass". Clearly, the solid outer surface could be one limit, but what about the waters? Lakes, rivers, wetlands, and especially the continental margins (continental shelf)?. If, and it's a big 'if', a projection of the surface is used (as a 2-dimensional surface) to determine center of 'mass', then what is done with surfaces covered with water? There are two other issues. First, the country's surface profile contains large changes in elevations. The surface distance between points A and B is not simply the 3-dimensional (coordinate) distance between them, but can be (and probably should be) best considered the geodesic shortest path ON THE SURFACE (up hills and mountains, down valleys and canyons, etc.) This adds surface area to any flat projection. The other problem is the use of the word "mass". Some readers will understand that a triangular area can have a 'center of mass' despite it being an abstract 2-dimensional massless object (or abstraction). Others will read 'center of mass' as a literal physically measurable thing. Well, for the latter, the mass of a given "core" of land varies with the densities of the (solid) materials it contains. The mass underneath a square meter of surface on the top of a Mt Denali will be different (almost certainly quite a bit more) than the mass underneath a square meter of Mississippi valley. Whether the term "underneath" describes the segment to the center of mass of the Earth, or to the bottom 'surface' of the lithosphere, crust, or some more or less arbitrary distance below the surface also should be defined. I'm not confident that we have sufficiently fine-grained information on the actual mass of the USA's landmass to calculate the "actual" center of mass (once limits are defined), but I'm confident we could determine the center of mass of an infinitely thin sheet conforming to the country's surface using USGS topographical information (as a good approximation). Whether this has been done, I don't know. IMHO, at the very least, the flaws of using an outline of the USA's 2-D border should be mentioned. (Especially if the border does not include the continental shelf which we claim.)98.17.181.251 (talk) 04:51, 28 June 2024 (UTC)[reply]