PgRaster
Sandro Santilli edited this page Mar 23, 2016
·
8 revisions
This plugin supports reading raster datasets from PostGIS.
Make sure that running python scons/scons.py
shows the following line
Checking for pg_config... yes
To check if the gdal plugin built and was installed correctly you can do:
>>> from mapnik import DatasourceCache as c
>>> 'pgraster' in c.plugin_names()
True
parameter | value | description | default |
---|---|---|---|
host | string | name of the postgres host | |
port | integer | name of the postgres port | |
dbname | string | name of the database | |
user | string | username to use for connecting | |
password | string | user password to use for connecting | |
table | string | name of the table to fetch, this can be a sub-query; subquery has to use syntax of: '( ) as subquery'. | |
raster_field | string | name of the raster field, in case you have more than one in a single table. This field and the SRID will be deduced from the query in most cases, but may need to be manually specified in some cases. | |
raster_table | string | name of the table containing the returned raster; for determining SRIDs with subselects | |
srid | integer | srid of the table, if this is > 0 then fetching data will avoid an extra database query for knowing the srid of the table | 0 |
extent | string | maxextent of the rasters | determined by querying the metadata for the table |
extent_from_subquery | boolean | evaluate the extent of the subquery, this might be a performance issue | false |
estimate_extent | boolean | estimate extent from statistics table if not specified | false |
connect_timeout | integer | timeout is seconds for the connection to take place | 4 |
persist_connection | boolean | choose whether to share the same connection for subsequent queries | true |
row_limit | integer | max number of rows to return when querying data, 0 means no limit | 0 |
cursor_size | integer | if this is > 0 then server cursor will be used, and will prefetch this number of features | 0 |
initial_size | integer | initial size of the stateless connection pool | 1 |
max_size | integer | max size of the stateless connection pool | 10 |
prescale_rasters | boolean | whether to automatically scale input rasters | false |
use_overviews | boolean | whether to use raster overviews when available | false |
clip_rasters | boolean | whether to automatically clip input rasters | false |
boolean |
DEPRECATED (automatically set internally based on max_async_connection > 1 condition) |
||
max_async_connection | integer | max number of PostGIS queries for rendering one map in asynchronous mode. Full doc here. |
1 |
band | integer | request for a specific raster band index (1-based). 0 means to read all bands. Note that a band read from a single band raster gets interpreted as Grayscale if band=0 is specified while they retain their original value when explicitly referenced with the "band" parameter. This affects effectiveness of RasterColorizer | 0 |