The Greenplum Database PostGIS extension package is available from Pivotal Network. You can install the package using the Greenplum Package Manager (gppkg). For details, see gppkg in the Greenplum Database Utility Guide.

For the information about supported extension packages and software versions see the Greenplum Database Release Notes.

Major enhancements and changes in PostGIS 2.1.5 from 2.0.3 include new PostGIS Raster functions. For a list of new and enhanced functions in PostGIS 2.1, see the PostGIS documentation PostGIS Functions new or enhanced in 2.1.

For a list of breaking changes in PostGIS 2.1, see PostGIS functions breaking changes in 2.1.

For a comprehensive list of PostGIS changes in PostGIS 2.1.5 and earlier, see PostGIS 2.1 Appendix A Release 2.1.5.

postgis_manager.sh mydatabase install

The script runs all the PostGIS SQL scripts that enable PostGIS in a database: install/postgis.sql, install/rtpostgis.sql install/spatial_ref_sys.sql, install/postgis_comments.sql, and install/raster_comments.sql.

The postGIS package installation adds these lines to the greenplum_path.sh file for PostGIS Raster support.

export GDAL_DATA=$GPHOME/share/gdal
export POSTGIS_ENABLE_OUTDB_RASTERS=0
export POSTGIS_GDAL_ENABLED_DRIVERS=DISABLE_ALL

PostGIS uses GDAL raster drivers when processing raster data with commands such as ST_AsJPEG(). As the default, PostGIS disables all raster drivers. You enable raster drivers by setting the value of the POSTGIS_GDAL_ENABLED_DRIVERS environment variable in the greenplum_path.sh file on all Greenplum Database hosts.

To see the list of supported GDAL raster drivers for a Greenplum Database system, run the raster2pgsql utility with the -G option on the Greenplum Database master.

raster2pgsql -G 

The command lists the driver long format name. The GDAL Raster Formats table at http://www.gdal.org/formats_list.html lists the long format names and the corresponding codes that you specify as the value of the environment variable. For example, the code for the long name Portable Network Graphics is PNG. This example export line enables four GDAL raster drivers.

export POSTGIS_GDAL_ENABLED_DRIVERS="GTiff PNG JPEG GIF"

The gpstop -r command restarts the Greenplum Database system to use the updated settings in the greenplum_path.sh file.

After you have updated the greenplum_path.sh file on all hosts, and have restarted the Greenplum Database system, you can display the enabled raster drivers with the ST_GDALDrivers() function. This SELECT command lists the enabled raster drivers.

SELECT short_name, long_name FROM ST_GDALDrivers();

postgis_manager.sh mydatabase uninstall

The script runs both the PostGIS SQL scripts that remove PostGIS and PostGIS Raster from a database: uninstall_rtpostgis.sql and uninstall_postgis.sql.

The postgis_manager.sh script does not remove these PostGIS Raster environment variables the greenplum_path.sh file: GDAL_DATA, POSTGIS_ENABLE_OUTDB_RASTERS, POSTGIS_GDAL_ENABLED_DRIVERS. The environment variables are removed when you uninstall the PostGIS extension package with the gppkg utility.

PostgreSQL provides support for GiST spatial indexing. The GiST scheme offers indexing even on large objects. It uses a system of lossy indexing in which smaller objects act as proxies for larger ones in the index. In the PostGIS indexing system, all objects use their bounding boxes as proxies in the index.

Greenplum Database PostGIS extension supports these PostGIS data types:

• box2d
• box3d
• geometry
• geography

For a list of PostGIS data types, operators, and functions, see the PostGIS reference documentation.

Greenplum Database PostGIS supports these PostGIS Raster data types.

• geomval
• addbandarg
• rastbandarg
• raster
• reclassarg
• summarystats
• unionarg

For information about PostGIS Raster data Management, queries, and applications http://postgis.net/docs/manual-2.1/using_raster_dataman.html

For a list of PostGIS Raster data types, operators, and functions, see the PostGIS Raster reference documentation.

Greenplum Database PostGIS extension supports the GiST (Generalized Search Tree) index.

This section lists the Greenplum Database PostGIS extension limitations for user-defined functions (UDFs), data types, and aggregates.

• Data types and functions related to PostGIS topology functionality, such as TopoGeometry, are not supported by Greenplum Database.
• Functions that perform ANALYZE operations for user-defined data types are not supported. For example, the ST_Estimated_Extent function is not supported. The function requires table column statistics for user defined data types that are not available with Greenplum Database.
• These PostGIS aggregates are not supported by Greenplum Database:
  • ST_MemCollect
  • ST_MakeLine

  On a Greenplum Database with multiple segments, the aggregate might return different answers if it is called several times repeatedly.

• Greenplum Database does not support PostGIS long transactions.

  PostGIS relies on triggers and the PostGIS table public.authorization_table for long transaction support. When PostGIS attempts to acquire locks for long transactions, Greenplum Database reports errors citing that the function cannot access the relation, authorization_table.

• Greenplum Database does not support type modifiers for user defined types.
  The work around is to use the AddGeometryColumn function for PostGIS geometry. For example, a table with PostGIS geometry cannot be created with the following SQL command:

  CREATE TABLE geometries(id INTEGER, geom geometry(LINESTRING));

  Use the AddGeometryColumn function to add PostGIS geometry to a table. For example, these following SQL statements create a table and add PostGIS geometry to the table:

  CREATE TABLE geometries(id INTEGER);
  SELECT AddGeometryColumn('public', 'geometries', 'geom', 0, 'LINESTRING', 2);

You can view comments with the pslq meta-command \dd function_name or from any tool that can show Greenplum Database function comments.

To remove PostGIS support from a database, run SQL scripts that are supplied with the PostGIS extension package in $GPHOME/share/postgresql/contrib/postgis-2.1/

gppkg -r postgis-2.1.5+pivotal.2

Restart Greenplum Database after removing the package.

gpstop -r

Ensure that these lines for PostGIS Raster support are removed from the greenplum_path.sh file.

export GDAL_DATA=$GPHOME/share/gdal
export POSTGIS_ENABLE_OUTDB_RASTERS=0
export POSTGIS_GDAL_ENABLED_DRIVERS=DISABLE_ALL