...now *this* is something that I know a great deal about (resulting in label placement in Google Maps and Google Earth, discussions with colleagues in USGS, the US Census Bureau, DoD, the United Nations GGIM experts group, UK Ordnance Survey, Survey of India, etc.)
Indeed most of the issues Andrey shared are significant, though the final note about "which map projection to use" is very odd. The "geographic center" however one might define it, is a geographic concept concerning place and not a cartographic concept concerning boundaries after projection. The computation only has its natural meaning on the globe. The typical choice is the lat-lon midpoint of the contiguous landmass (easy) or major aggregate areas (more handwavy) such as would be the case in Michigan <https://www.google.com/maps/place/Michigan/@45.1616862,-85.8495266,6.82z/data=!4m5!3m4!1s0x4d4caa3dc7ca0411:0x97dd48597a62c9b3!8m2!3d44.3148443!4d-85.6023643> in the United States. Note that the link shows the two major areas as well as a large Isle Royale National Park to the north. The question being to include it or not. The same issue arises with Stewart Island in New Zealand. There is a pragmatic issue as well--the center may not be in the geographic entity at all! Imagine a 'C' shaped land. Such a land mass will have a center, computed by any reasonable means, that is in the empty center and not in the surrounding ring. Does this happen? Yes, thousands of times <https://www.google.com/maps/place/Molokini/@20.6323227,-156.4981647,17z/data=!3m1!4b1!4m5!3m4!1s0x7954dc72c0456efd:0xa0679505e267d06b!8m2!3d20.6309516!4d-156.4954163>. Note the placement of "Molokini Shoal Marine Life Conservation District" compared to the "Molokini" point of interest label--any "center" is along the line segment between these yet most are offshore. Same in Ecuador with its Galápagos Islands, where the midpoint is in the ocean. (The same thing happens with 'L' shaped regions, such as Florida in the United States, and hook or curved places including Cuba, Laos, Vietnam, and Norway.) The story of Richard Feynman's travels to the center of Asia <https://en.wikipedia.org/wiki/Geographical_midpoint_of_Asia> is chronicled in Ralph Leighton's delightful book "Tuva or Bust. <https://www.amazon.com/Tuva-Bust-Richard-Feynmans-Journey/dp/0393320693>" (Note that at least three places are claimed as the center of Asia.) On Sat, Dec 7, 2019 at 8:38 AM andrey mirtchovski <mirtchov...@gmail.com> wrote: > this is quickly becoming off-topic. however, from > https://en.wikipedia.org/wiki/Geographical_centre: > > "As noted in a USGS document "There is no generally accepted > definition of geographic center, and no completely satisfactory method > for determining it."[1] > > 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." > -- > [1]: https://pubs.er.usgs.gov/publication/70039437 > > On Sat, Dec 7, 2019 at 9:32 AM JuciÊ Andrade <oju...@gmail.com> wrote: > > > > If one wants to improve precision she may use a bigger map. > > The resulting position would be the same, only more accurate. > > > > -- > > You received this message because you are subscribed to the Google > Groups "golang-nuts" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to golang-nuts+unsubscr...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/270e41e1-5dd5-4351-be8a-1ba683bdd6a8%40googlegroups.com > . > > -- > You received this message because you are subscribed to the Google Groups > "golang-nuts" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/CAK4xykV5zOMW%2Bbv3DWb1pTXad-rieqnYdoop6dpJwmsnkkGx2w%40mail.gmail.com > . > -- *Michael T. jonesmichael.jo...@gmail.com <michael.jo...@gmail.com>* -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CALoEmQzm1V3FUaQ0PYfaKwY0wkk1rwRZcZjub_08hgdfkLJFrw%40mail.gmail.com.
