Experts meet to decide Pluto fate, Finally we'll know what a 'planet' is... |
Experts meet to decide Pluto fate, Finally we'll know what a 'planet' is... |
Aug 14 2006, 06:06 AM
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#1
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Member Group: Members Posts: 295 Joined: 2-March 04 From: Central California Member No.: 45 |
-------------------- Eric P / MizarKey
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Aug 16 2006, 06:08 PM
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#2
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Solar System Cartographer Group: Members Posts: 10164 Joined: 5-April 05 From: Canada Member No.: 227 |
As a rule of thumb for whether a non-spherical world should be mapped on a conventional map projection or a special one (like my morphographic projections), I have said in the past that a 10 percent difference between max and min radii makes a sensible division. Earth's max and min radii (center of mass to top of lithosphere, Chimborazo to floor of Arctic Ocean) differ by 0.5 percent. But like all these choices it's purely arbitrary, and in a situation where shapes will usually be poorly known this will be a serious problem.
People want definitions to be like fences, but usually they are central conditions with fuzzy edges. I have no problem calling Ceres a planet, but I'm utterly mystified by the idea that Charon should be one. It's a satellite. Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Aug 16 2006, 07:17 PM
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#3
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Member Group: Members Posts: 809 Joined: 11-March 04 Member No.: 56 |
As a rule of thumb for whether a non-spherical world should be mapped on a conventional map projection or a special one (like my morphographic projections), I have said in the past that a 10 percent difference between max and min radii makes a sensible division. Is that: if the maximum is 110% of the minimum? Or: if the minimum is 90% of the maximum? |
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