Changes between Version 1 and Version 2 of Ticket #12314, comment 1


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Timestamp:
Jan 3, 2017, 1:53:44 PM (6 years ago)
Author:
awulkiew

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  • Ticket #12314, comment 1

    v1 v2  
    1 In non-cartesian coordinate systems the edges of Polygons are also shortest lines between points so e.g. the edge: `(0 89, 180 89)` intersects the north pole. In the case of the edge `(180 0, 0 0)` I'm not sure what the algorithm assumes but this edge is invalid. The reason for that is that there is infinite number possible edges connecting these points in spherical and 2 possible edges in geographic (going through north or south pole). Either way I presume this is not what you had in mind.
     1In non-cartesian coordinate systems the edges of Polygons are also shortest lines between points so e.g. the edge: `(0 89, 180 89)` intersects the north pole. In the case of the edge `(180 0, 0 0)` I'm not sure what the algorithm assumes but this edge is invalid. The reason for that is that there is infinite number of possible edges connecting these points in spherical and 2 possible edges in geographic (going through north or south pole). Either way I presume this is not what you had in mind.
    22
    33You could fix the invalidity by adding additional point between the invalid edge, so: `POLYGON((0 89, 180 89, 180 0, 90 0, 0 0, 0 89 ))` but this is not what you wanted to do either.