# Tag Info

## New answers tagged srid

2

You have most probably inverted the Lat and Lng values in either Leaflet or PostGIS. Let's have: Point1: Lat: -12.99835864475412 / Lng: -38.506194949150085 Point2: Lat: -12.999215865191118 / Lng: -38.50590527057648 Point3: Lat: -38.506194949150085 / Lng: -12.99835864475412 (inverted from Point1) Point4: Lat: -38.50590527057648 / Lng: -12.999215865191118 ...

2

The reason the Haversine equation is used for the 4326 calculation is that this is a geographic coordinate system. That means that the coordinates are still on a sphere, they are not mathematically transformed to a flat surface. A projected coordinate system would have this equation or some similar construct already "built-in", so to speak. The Web Mercator ...

1

Buffer does not seem to support any extra parameters with geography http://postgis.net/docs/ST_Buffer.html. However, with geometry you can control the number of segments with num_seg_quarter_circle. You need to cast your geography into geometry before using ST_Buffer with num_seg_quarter_circle parameter and finally cast the result back to geography. Try ...

0

Haversine distance formula calculates on a sphere, which is going to be a closer calculation than a straight line distance calculation that does not take into consideration the curvature of the Earth. This Math SE Q&A may give you some additional insight. From link: The Haversine formula gives the "as-the-crow-flies" distance, i.e., the great ...

0

SELECT ST_AsEWKT( ST_SetSRID( St_GeometryFromText(' MULTIPOLYGON(((295098.566494 6006717.0377012,344018.26458971 6009163.022606,329342.355161 5972473.2490342,295098.566494 6006717.0377012))) ') ,900913) ) SELECT ST_AsText( ST_SetSRID( St_GeometryFromText(' MULTIPOLYGON(((295098.566494 6006717.0377012,344018.26458971 6009163.022606,329342.355161 ...

3

If you run, using your original geometry: SELECT ST_AsText( ST_GeomFromEWKT('010600002031BF0D000100000001030000000100000004000000CE001744EA0212414BB26942EFE95641DD9AF00E49FF1441706072C152EC56413F53AF6BF9191441242DF04F7EC85641CE001744EA0212414BB26942EFE95641' )); you will see: MULTIPOLYGON(((295098.566494 ...

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