Contents
How to find the SRID of the geometry column?
Returns the integer SRID of the specified geometry column by searching through the GEOMETRY_COLUMNS table. If the geometry column has not been properly added (e.g. with the AddGeometryColumn function), this function will not work.
Can you generate random points inside a polygon?
Generating random points until one is inside the polygon wouldn’t work because it’s really unpredictable the time it takes. On the contrary, the time is predictable. It is proportional to the ratio of the polygon’s extent area divided by the polygon’s area, times the time needed to generate and test a single point.
How to return the area of a polygon?
Area: Return the area of a polygon (0 for an empty polygon). BoundingBox: Return the bounding box (extent) of a polygon. Width: Return the width of a rectangle. Height: Return the height of a rectangle. Left: Split a rectangle into two halves and return the left half.
How to calculate the distance in a spheroid?
New variable for calculates the distance in spheroid or ellipsoid. Input any SRID, function transform Geom to the working environment of Spheroid or Ellipsoid Datum, then apply the distance to each side, get the result and transform to input SRID.
How do you know what srid to use for a shp file?
The search tool is primitive so you may have to use a Google search and specify the site, but any results will show you the ESRI PRJ contents, the PostGIS SQL INSERT, and a bunch of other representations. Prj2EPSG is a small website aimed at exactly this problem; paste in the PRJ contents and it does its best to find a matching EPSG.
Is the SRID the same as the EPSG code?
To elaborate on synecdoche’s answer, the SRID is sometimes called an “EPSG” code. The SRID/EPSG code is a defacto short-hand for the Well-Known-Text representations of projections. You can do a quick search on the SRID table to see if you can find an exact or similar match: