flowmachine.features.raster.raster_statistics¶

Source: flowmachine/features/raster/raster_statistics.py

Utility method for calculating raster statistics.

Class RasterStatistics¶

RasterStatistics(
    raster,
    band=1,
    vector=None,
    vector_property="geom",
    grouping_element=None,
    statistic="sum",
)

Source: flowmachine/features/raster/raster_statistics.py

Class for calculating raster statistics. Credit for original solution goes to: http://movingspatial.blogspot.co.uk/2012/07/postgis-20-intersect-raster-and-polygon.html

Parameters¶

raster: str

Fully qualified table name of raster data. This assumes that raster table contains a column named rast.
band: array, int

Band number to use for calculations. Default is band 1. For multiple bands, use array: [1, 2]
vector: str

Vector layer to use in case of clipping and grouping operations. If this option is provided, the parameters vector_property and grouping_element need to be provided. This can also be a Query object which returns a geometry column.
vector_property: str

Column name from vector layer with geometry data. This is usually called geom, but can be something else.
grouping_element: str

Column name of grouping property to use for aggregating values. This property should be an equivalent human-readable to the values in the vector_property column.
statistic: str

Type of statistic to calculate from raster. Only sum is supported at the moment.

Methods¶

cache¶

cache

Source: flowmachine/core/query.py

Returns¶

bool

True is caching is switched on.

column_names¶

column_names

Source: flowmachine/features/raster/raster_statistics.py

Returns the column names.

Returns¶

typing.List

List of the column names of this query.

column_names_as_string_list¶

column_names_as_string_list

Source: flowmachine/core/query.py

Get the column names as a comma separated list

Returns¶

str

Comma separated list of column names

dependencies¶

dependencies

Source: flowmachine/core/query.py

Returns¶

set

The set of queries which this one is directly dependent on.

fully_qualified_table_name¶

fully_qualified_table_name

Source: flowmachine/core/query.py

Returns a unique fully qualified name for the query to be stored as under the cache schema, based on a hash of the parameters, class, and subqueries.

Returns¶

str

String form of the table's fqn

index_cols¶

index_cols

Source: flowmachine/core/query.py

A list of columns to use as indexes when storing this query.

Returns¶

ixen: list

By default, returns the location columns if they are present and self.spatial_unit is defined, and the subscriber column.

Examples¶

daily_location("2016-01-01").index_cols
[['name'], '"subscriber"']

is_stored¶

is_stored

Source: flowmachine/core/query.py

Returns¶

bool

True if the table is stored, and False otherwise.

query_id¶

query_id

Source: flowmachine/core/query.py

Generate a uniquely identifying hash of this query, based on the parameters of it and the subqueries it is composed of.

Returns¶

str

query_id hash string

query_state¶

query_state

Source: flowmachine/core/query.py

Return the current query state.

Returns¶

QueryState

The current query state

query_state_str¶

query_state_str

Source: flowmachine/core/query.py

Return the current query state as a string

Returns¶

str

The current query state. The possible values are the ones defined in flowmachine.core.query_state.QueryState.

table_name¶

table_name

Source: flowmachine/core/query.py

Returns a uniquename for the query to be stored as, based on a hash of the parameters, class, and subqueries.

Returns¶

str

String form of the table's fqn