23.2.8. Vector miscellaneous

23.2.8.1. Build virtual vector

Creates a virtual vector layer that contains a set of vector layers. The output virtual vector layer will not be opened in the current project.

This algorithm is especially useful in case another algorithm needs multiple layers but accept only one vrt in which the layers are specified.

23.2.8.1.1. Parameters

Label

Name

Type

Description

Input datasources

INPUT

[vector: any] [list]

Select the vector layers you want to use to build the virtual vector

Create “unioned” VRT

UNIONED

[boolean]

Default: False

Check if you want to unite all the vectors in a single vrt file

Virtual vector

OUTPUT

[same as input]

Default: [Save to temporary file]

Specify the output layer containing only the duplicates. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.8.1.2. Outputs

Label

Name

Type

Description

Virtual vector

OUTPUT

[vector: any]

The output virtual vector made from the chosen sources

23.2.8.1.3. Python code

Algorithm ID: gdal:buildvirtualvector

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

23.2.8.2. Execute SQL

Runs a simple or complex query with SQL syntax on the source layer. The result of the query will be added as a new layer.

This algorithm is derived from the GDAL ogr2ogr utility.

23.2.8.2.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

OGR-supported input vector layer

SQL expression

SQL

[string]

Defines the SQL query, for example SELECT * FROM my_table WHERE name is not null.

SQL dialect

DIALECT

[enumeration]

Default: 0

SQL dialect to use. One of:

  • 0 — None

  • 1 — OGR SQL

  • 2 — SQLite

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

SQL result

OUTPUT

[vector: any]

Specification of the output layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

For Save to File, the output format has to be specified. All GDAL vector formats are supported. For Save to a Temporary File the default output vector layer format will be used.

23.2.8.2.2. Outputs

Label

Name

Type

Description

SQL result

OUTPUT

[vector: any]

Vector layer created by the query

23.2.8.2.3. Python code

Algorithm ID: gdal:executesql

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

23.2.8.3. Export to PostgreSQL (available connections)

Imports vector layers inside a PostgreSqL database on the basis of an available connection. The connection has to be defined properly beforehand. Be aware that the checkboxes ‘Save Username’ and ‘Save Password’ are activated. Then you can use the algorithm.

This algorithm is derived from the GDAL ogr2ogr utility.

23.2.8.3.1. Parameters

Label

Name

Type

Description

Database (connection name)

DATABASE

[string]

The PostgreSQL database to connect to

Input layer

INPUT

[vector: any]

OGR-supported vector layer to export to the database

Shape encoding

Optional

SHAPE_ENCODING

[string]

Default: ‘’

Sets the encoding to apply to the data

Output geometry type

GTYPE

[enumeration]

Default: 0

Defines the output geometry type. One of:

  • 0 —

  • 1 — NONE

  • 2 — GEOMETRY

  • 3 — POINT

  • 4 — LINESTRING

  • 5 — POLYGON

  • 6 — GEOMETRYCOLLECTION

  • 7 — MULTIPOINT

  • 8 — MULTIPOLYGON

  • 9 — MULTILINESTRING

Assign an output CRS

Optional

A_SRS

[crs]

Default: None

Defines the output CRS of the database table

Reproject to this CRS on output

Optional

T_SRS

[crs]

Default: None

Reprojects/transforms to this CRS on output

Override source CRS

Optional

S_SRS

[crs]

Default: None

Overrides the input layer CRS

Schema (schema name)

Optional

SCHEMA

[string]

Default: ‘public’

Defines the schema for the database table

Table to export to (leave blank to use layer name)

Optional

TABLE

[string]

Default: ‘’

Defines a name for the table that will be imported into the database. By default the table name is the name of the input vector file.

Primary Key (new field)

Optional

PK

[string]

Default: ‘id’

Defines which attribute field will be the primary key of the database table

Primary Key (existing field, used if the above option is left empty)

Optional

PRIMARY_KEY

[tablefield: any]

Default: None

Defines which attribute field in the exported layer will be the primary key of the database table

Geometry column name

Optional

GEOCOLUMN

[string]

Default: ‘geom’

Defines in which attribute field of the database there will be the geometry information

Vector dimensions

Optional

DIM

[enumeration]

Default: 0 (2D)

Defines if the vector file to be imported has 2D or 3D data. One of:

  • 0 — 2

  • 1 — 3

Distance tolerance for simplification

Optional

SIMPLIFY

[string]

Default: ‘’

Defines a distance tolerance for the simplification of the vector geometries to be imported. By default there is no simplification.

Maximum distance between 2 nodes (densification)

Optional

SEGMENTIZE

[string]

Default: ‘’

The maximum distance between two nodes. Used to create intermediate points. By default there is no densification.

Select features by extent (defined in input layer CRS)

Optional

SPAT

[extent]

Default: None

You can select features from a given extent that will be in the output table.

Clip the input layer using the above (rectangle) extent

Optional

CLIP

[boolean]

Default: False

The input layer will be clipped by the extent you defined before

Select features using a SQL “WHERE” statement (Ex: column=”value”)

Optional

WHERE

[string]

Default: ‘’

Defines with a SQL “WHERE” statement which features should be selected from the input layer

Group N features per transaction (Default: 2000)

Optional

GT

[string]

Default: ‘’

You can group the input features in transactions where N defines the size. By default N limits the transaction size to 20000 features.

Overwrite existing table

Optional

OVERWRITE

[boolean]

Default: True

If there is a table with the same name in the database, and if this option is set to True, the table will be overwritten.

Append to existing table

Optional

APPEND

[boolean]

Default: False

If checked / True the vector data will be appended to an existing table. New fields found in the input layer are ignored. By default a new table will be created.

Append and add new fields to existing table

Optional

ADDFIELDS

[boolean]

Default: False

If activated the vector data will be appended to an existing table, there won’t be a new table created. New fields found in input layer are added to the table. By default a new table will be created.

Do not launder columns/table names

Optional

LAUNDER

[boolean]

Default: False

With this option checked you can prevent the default behaviour (converting column names to lowercase, removing spaces and other invalid characters).

Do not create Spatial Index

Optional

INDEX

[boolean]

Default: False

Prevents a spatial index for the output table from being created. By default, a spatial index is added.

Continue after a failure, skipping the failed feature

Optional

SKIPFAILURES

[boolean]

Default: False

Promote to Multipart

Optional

PROMOTETOMULTI

[boolean]

Default: True

Casts features geometry type to multipart in the output table

Keep width and precision of input attributes

Optional

PRECISION

[boolean]

Default: True

Avoids modifying column attributes to comply with input data

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

23.2.8.3.2. Outputs

This algorithm has no output.

23.2.8.3.3. Python code

Algorithm ID: gdal:importvectorintopostgisdatabaseavailableconnections

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

23.2.8.4. Export to PostgreSQL (new connection)

Imports vector layers inside a PostGreSQL database. A new connection to the PostGIS database must be created.

This algorithm is derived from the GDAL ogr2ogr utility.

23.2.8.4.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

OGR-supported vector layer to export to the database

Shape encoding

Optional

SHAPE_ENCODING

[string]

Default: ‘’

Sets the encoding to apply to the data

Output geometry type

GTYPE

[enumeration]

Default: 0

Defines the output geometry type. One of:

  • 0 —

  • 1 — NONE

  • 2 — GEOMETRY

  • 3 — POINT

  • 4 — LINESTRING

  • 5 — POLYGON

  • 6 — GEOMETRYCOLLECTION

  • 7 — MULTIPOINT

  • 8 — MULTIPOLYGON

  • 9 — MULTILINESTRING

Assign an output CRS

Optional

A_SRS

[crs]

Default: None

Defines the output CRS of the database table

Reproject to this CRS on output

Optional

T_SRS

[crs]

Default: None

Reprojects/transforms to this CRS on output

Override source CRS

Optional

S_SRS

[crs]

Default: None

Overrides the input layer CRS

Host

Optional

HOST

[string]

Default: ‘localhost’

Name of the database host

Port

Optional

PORT

[string]

Default: ‘5432’

Port number the PostgreSQL database server listens on

Username

Optional

USER

[string]

Default: ‘’

User name used to log in to the database

Database name

Optional

DBNAME

[string]

Default: ‘’

Name of the database

Password

Optional

PASSWORD

[string]

Default: ‘’

Password used with Username to connect to the database

Schema (schema name)

Optional

SCHEMA

[string]

Default: ‘public’

Defines the schema for the database table

Table name, leave blank to use input name

Optional

TABLE

[string]

Default: ‘’

Defines a name for the table that will be imported into the database. By default the table name is the name of the input vector file.

Primary Key (new field)

Optional

PK

[string]

Default: ‘id’

Defines which attribute field will be the primary key of the database table

Primary Key (existing field, used if the above option is left empty)

Optional

PRIMARY_KEY

[tablefield: any]

Default: None

Defines which attribute field in the exported layer will be the primary key of the database table

Geometry column name

Optional

GEOCOLUMN

[string]

Default: ‘geom’

Defines in which attribute field to store the geometry information

Vector dimensions

Optional

DIM

[enumeration]

Default: 0 (2D)

Defines if the vector file to be imported has 2D or 3D data. One of:

  • 0 — 2D

  • 1 — 3D

Distance tolerance for simplification

Optional

SIMPLIFY

[string]

Default: ‘’

Defines a distance tolerance for the simplification of the vector geometries to be imported. By default no simplification there is no simplification.

Maximum distance between 2 nodes (densification)

Optional

SEGMENTIZE

[string]

Default: ‘’

The maximum distance between two nodes. Used to create intermediate points. By default there is no densification.

Select features by extent (defined in input layer CRS)

Optional

SPAT

[extent]

Default: None

You can select features from a given extent that will be in the output table.

Clip the input layer using the above (rectangle) extent

Optional

CLIP

[boolean]

Default: False

The input layer will be clipped by the extent you defined before

Fields to include (leave empty to use all fields)

Optional

FIELDS

[string] [list]

Default: []

Defines fields to keep from the imported vector file. If none is selected, all the fields are imported.

Select features using a SQL “WHERE” statement (Ex: column=”value”)

Optional

WHERE

[string]

Default: ‘’

Defines with a SQL “WHERE” statement which features should be selected for the output table

Group N features per transaction (Default: 2000)

Optional

GT

[string]

Default: ‘’

You can group the input features in transactions where N defines the size. By default N limits the transaction size to 20000 features.

Overwrite existing table

Optional

OVERWRITE

[boolean]

Default: True

If there is a table with the same name in the database, and if this option is set to True, the table will be overwritten.

Append to existing table

Optional

APPEND

[boolean]

Default: False

If checked / True the vector data will be appended to an existing table. New fields found in the input layer are ignored. By default a new table will be created.

Append and add new fields to existing table

Optional

ADDFIELDS

[boolean]

Default: False

If activated the vector data will be appended to an existing table, there won’t be created a new table. New fields found in input layer are added to the table. By default a new table will be created.

Do not launder columns/table names

Optional

LAUNDER

[boolean]

Default: False

With this option checked you can prevent the default behaviour (converting column names to lowercase, removing spaces and other invalid characters).

Do not create Spatial Index

Optional

INDEX

[boolean]

Default: False

Prevents a spatial index for the output table from being created. By default, a spatial index is added.

Continue after a failure, skipping the failed feature

Optional

SKIPFAILURES

[boolean]

Default: False

Promote to Multipart

Optional

PROMOTETOMULTI

[boolean]

Default: True

Casts features geometry type to multipart in the output table

Keep width and precision of input attributes

Optional

PRECISION

[boolean]

Default: True

Avoids modifying column attributes to comply with input data

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

23.2.8.4.2. Outputs

This algorithm has no output.

23.2.8.4.3. Python code

Algorithm ID: gdal:importvectorintopostgisdatabasenewconnection

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.

23.2.8.5. Vector Information

Creates an information file that lists information about an OGR-supported data source. The output will be shown in a ‘Result’ window and can be written into a HTML-file. The information includes the geometry type, feature count, the spatial extent, the projection information and many more.

This algorithm is derived from the GDAL ogrinfo utility.

23.2.8.5.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

Input vector layer

Summary output only

Optional

SUMMARY_ONLY

[boolean]

Default: True

Suppress metadata info

Optional

NO_METADATA

[boolean]

Default: False

Layer information

OUTPUT

[html]

Default: [Save to temporary file]

Specify the output HTML file that includes the file information. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here. If no HTML-file is defined the output will be written to a temporary file

23.2.8.5.2. Outputs

Label

Name

Type

Description

Layer information

OUTPUT

[html]

The output HTML-file that includes the file information.

23.2.8.5.3. Python code

Algorithm ID: gdal:ogrinfo

import processing
processing.run("algorithm_id", {parameter_dictionary})

The algorithm id is displayed when you hover over the algorithm in the Processing Toolbox. The parameter dictionary provides the parameter NAMEs and values. See Using processing algorithms from the console for details on how to run processing algorithms from the Python console.