[DOCS-1391] 2dsphere bounding polygon must be <= hemisphere Created: 13/Apr/13 Updated: 30/Oct/23 Resolved: 16/Apr/13 |
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| Status: | Closed |
| Project: | Documentation |
| Component/s: | Server |
| Affects Version/s: | None |
| Fix Version/s: | Server_Docs_20231030 |
| Type: | Improvement | Priority: | Major - P3 |
| Reporter: | Daniel Pasette (Inactive) | Assignee: | Sam Kleinman (Inactive) |
| Resolution: | Done | Votes: | 0 |
| Labels: | None | ||
| Remaining Estimate: | Not Specified | ||
| Time Spent: | Not Specified | ||
| Original Estimate: | Not Specified | ||
| Issue Links: |
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| Participants: | |||||||||
| Days since reply: | 10 years, 44 weeks, 1 day ago | ||||||||
| Description |
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See: https://groups.google.com/forum/?fromgroups=#!topic/mongodb-user/D7ZMWdUnR5U If the x-axis spans more than 180° it is an invalid shape for $geoWithin or $geoIntersects. For example:
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| Comments |
| Comment by auto [ 16/Apr/13 ] |
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Author: {u'date': u'2013-04-16T16:15:45Z', u'name': u'Sam Kleinman', u'email': u'samk@10gen.com'}Message: |
| Comment by Daniel Pasette (Inactive) [ 16/Apr/13 ] |
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schwerin claims that there is a convention for how to handle large polygons based on the order in which you "walk" the coordinates. For example, if you walk the coordinates in a clockwise direction, everything on your "right" would be inside the polygon. GeoJSON explicitly shies away from dictating this directly. See this thread: http://lists.geojson.org/pipermail/geojson-geojson.org/2007-October/000273.html Neither SQL Server nor PostGIS handle > 180° bounding polygons. aka, the "hemisphere limitation" |
| Comment by Daniel Pasette (Inactive) [ 15/Apr/13 ] |
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As a further tool that we may want to consider including in our documentation to illustrate how great arcs work when you create a bounding polygon. It was instructive to me how these look transposed onto the globe by this great circle rendering site. If the polygon is greater than 180° of long, we have no way of knowing which "side" the polygon is trying to describe and GeoJSON has no way to denote this – GeoJSON doesn't have support for "orientation" (E,N,S,W). Note how this very "broad" (179° of long) poly renders: vs. a polygon that could be thought of as extending beyond 180° (it doesn't : Hope this helps. |