NGSIPostGISSink

Content:

• Functionality
• Administration guide
• Programmers guide
• Native types

Functionality

com.iot.telefonica.cygnus.sinks.NGSIPostGISSink, or simply NGSIPostGISSink is a sink designed to persist NGSI-like context data events within a PostGIS server which is relational database extension of PostgreSQL server which allows store GIS objects (Geographic Information Systems). Usually, such a context data is notified by a Orion Context Broker instance, but could be any other system speaking the NGSI language.

Independently of the data generator, NGSI context data is always transformed into internal NGSIEvent objects at Cygnus sources. In the end, the information within these events must be mapped into specific PostgreSQL data structures.

For futher detail please refear to NGSIPostgreSQLSink Basically PostGIS sink translates NGSI attribute value about geometry (geo:point, geo:json) to PostGIS format and insert it.

geo:point ->  ST_SetSRID(ST_MakePoint())

geo:json -> ST_GeomFromGeoJSON()

Colum should be provisioned as type geometry

CREATE TABLE myTable ( geom geometry );

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Administration guide

Please refear to NGSIPostgreSQLSink since all administration options about PostgreSQLSink applies to PostGISSink.

Programmers guide

Please refear to NGSIPostgreSQLSink since all programing details about PostgreSQLSink applies to PostGISSink.

Native types

Regarding the specific data stored within the above table, if attr_native_types parameter is set to true then attribute is inserted using its native type (according with the following table), if false then will be stringify.

Type json	Type PostGreSQL/POSTGIS
string	text
number	double, precision, real, others (numeric, decimal)
boolean	boolean (TRUE, FALSE, NULL)
DateTime	timestamp, timestamp with time zone, timestamp without time zone
json	text o json - it`s treated as String
null	NULL

This only applies to Column mode.