Is the S2 library based on the WGS-84 coordinate system? #311
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I looked at the official documents, but I didn't find any instructions about WGS-84. I want to confirm it. |
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Replies: 3 comments 4 replies
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No, everything is based on a sphere. |
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s2earth radius is the mean radius which averages the difference between
polar and equatorial radius. It's 6,371.0088 km which is the same as the
WGS-84 mean radius.
…On Thu, Apr 13, 2023 at 6:43 AM Jesse Rosenstock ***@***.***> wrote:
No, everything is based on a sphere. s2earth.h has a radius, but I'm not
sure how it compares to the equivalent radius of the WGS 84 spheroid.
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@smcallis Can I think that the geographical calculation results based on the S2 library are in line with the WGS 84 coordinate system？ |
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No in general no because there's no ellipsoidal correction, so distances and areas won't be the same. The error is small but noticeable. |
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last question：Is the geography_functions in bigquery implemented based on the S2 library? |
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Those are implemented based on a library called STLib which is built on top
of S2 but isn't open sourced (yet).
…On Thu, Apr 13, 2023 at 9:36 PM Liqf ***@***.***> wrote:
last question：Is the geography_functions in bigquery implemented based on
the S2 library?
https://cloud.google.com/bigquery/docs/reference/standard-sql/geography_functions
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thks |
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No in general no because there's no ellipsoidal correction, so distances and areas won't be the same. The error is small but noticeable.