Module: PostgisAdapter::Functions::PolygonFunctions

Defined in:
lib/postgis_adapter/functions/common.rb

Overview

Polygon

Instance Method Summary collapse

Instance Method Details

#area(transform = nil) ⇒ Object

The area of the geometry if it is a polygon or multi-polygon. Return the area measurement of an ST_Surface or ST_MultiSurface value. Area is in the units of the spatial reference system.

Accepts optional parameter, the srid to transform to.

Returns Float ST_Area(geometry g1);



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# File 'lib/postgis_adapter/functions/common.rb', line 836

def area transform=nil
  postgis_calculate(:area, self, { :transform => transform }).to_f
end

#closed? ⇒ Boolean Also known as: is_closed?

True if the LineString’s start and end points are coincident.

This method implements the OpenGIS Simple Features Implementation Specification for SQL.

SQL-MM defines the result of ST_IsClosed(NULL) to be 0, while PostGIS returns NULL.

Returns boolean ST_IsClosed(geometry g);

Returns:

  • (Boolean) 


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# File 'lib/postgis_adapter/functions/common.rb', line 874

def closed?
  postgis_calculate(:isclosed, self)
end

#covers?(other) ⇒ Boolean

True if no point in Geometry B is outside Geometry A

This function call will automatically include a bounding box comparison that will make use of any indexes that are available on the geometries. To avoid index use, use the function _ST_Covers.

Do not call with a GEOMETRYCOLLECTION as an argument Do not use this function with invalid geometries. You will get unexpected results.

Performed by the GEOS module.

Returns Boolean ST_Covers(geometry geomA, geometry geomB);

Returns:

  • (Boolean) 


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# File 'lib/postgis_adapter/functions/common.rb', line 893

def covers? other
  postgis_calculate(:covers, [self, other])
end

#perimeter(transform = nil) ⇒ Object

Returns the 2D perimeter of the geometry if it is a ST_Surface, ST_MultiSurface (Polygon, Multipolygon). 0 is returned for non-areal geometries. For linestrings use ‘length’. Measurements are in the units of the spatial reference system of the geometry.

Accepts optional parameter, the sridto transform to.

Returns Float ST_Perimeter(geometry g1);



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# File 'lib/postgis_adapter/functions/common.rb', line 850

def perimeter transform=nil
  postgis_calculate(:perimeter, self, { :transform => transform }).to_f
end

#perimeter3d ⇒ Object

Returns the 3-dimensional perimeter of the geometry, if it is a polygon or multi-polygon. If the geometry is 2-dimensional, then the 2-dimensional perimeter is returned.

Returns Float ST_Perimeter3D(geometry geomA);



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# File 'lib/postgis_adapter/functions/common.rb', line 860

def perimeter3d
  postgis_calculate(:perimeter3d, self).to_f
end