postgis-workshop/geometries — Spanish @ OSGeo Weblate: :command:`ST_Area(geometry)` returns the area of the polygons

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	The street network for New York (``nyc_streets``) was loaded earlier in the workshop. This dataset contains details such as name, and type. A single real world street may consist of many linestrings, each representing a segment of road with different attributes.
	The following SQL query will return the geometry associated with one linestring (in the :command:`ST_AsText` column).
	Some of the specific spatial functions for working with linestrings are:
	:command:`ST_Length(geometry)` returns the length of the linestring
	:command:`ST_StartPoint(geometry)` returns the first coordinate as a point
	:command:`ST_EndPoint(geometry)` returns the last coordinate as a point
	:command:`ST_NPoints(geometry)` returns the number of coordinates in the linestring
	So, the length of our linestring is:
	Polygons
	A polygon is a representation of an area. The outer boundary of the polygon is represented by a ring. This ring is a linestring that is both closed and simple as defined above. Holes within the polygon are also represented by rings.
	Polygons are used to represent objects whose size and shape are important. City limits, parks, building footprints or bodies of water are all commonly represented as polygons when the scale is sufficiently high to see their area. Roads and rivers can sometimes be represented as polygons.
	The following SQL query will return the geometry associated with one polygon (in the :command:`ST_AsText` column).
	Rather than using an ``=`` sign in our ``WHERE`` clause, we are using the ``LIKE`` operator to carry out a string matching operation. *You may be used to the ```` symbol as a "glob" for pattern matching, but in SQL the ``%`` symbol is used**, along with the ``LIKE`` operator to tell the system to do globbing.
	The first polygon has only one ring. The second one has an interior "hole". Most graphics systems include the concept of a "polygon", but GIS systems are relatively unique in allowing polygons to explicitly have holes.
	Some of the specific spatial functions for working with polygons are:
	:command:`ST_Area(geometry)` returns the area of the polygons	:command:`ST_Area(geometría)` devuelve el área de la geometría.
	:command:`ST_NRings(geometry)` returns the number of rings (usually 1, more if there are holes)
	:command:`ST_ExteriorRing(geometry)` returns the outer ring as a linestring
	:command:`ST_InteriorRingN(geometry,n)` returns a specified interior ring as a linestring
	:command:`ST_Perimeter(geometry)` returns the length of all the rings
	We can calculate the area of our polygons using the area function:
	Note that the polygon with a hole has an area that is the area of the outer shell (a 10x10 square) minus the area of the hole (a 1x1 square).
	Collections
	There are four collection types, which group multiple simple geometries into sets.
	MultiPoint, a collection of points
	MultiLineString, a collection of linestrings
	MultiPolygon, a collection of polygons
	GeometryCollection, a heterogeneous collection of any geometry (including other collections)
	Collections are another concept that shows up in GIS software more than in generic graphics software. They are useful for directly modeling real world objects as spatial objects. For example, how to model a lot that is split by a right-of-way? As a MultiPolygon, with a part on either side of the right-of-way.
	Our example collection contains a polygon and a point:
	Some of the specific spatial functions for working with collections are: