23.2.7. Vector geoprocessing

23.2.7.1. Buffer vectors

Create buffers around the features of a vector layer.

23.2.7.1.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

The input vector layer

Geometry column name

GEOMETRY

[string]

Default: ‘geometry’

The name of the input layer geometry column to use

Buffer distance

DISTANCE

[number]

Default: 10.0

Minimum: 0.0

Dissolve by attribute

Optional

FIELD

[tablefield: any]

Default: None

Field to use for dissolving

Dissolve results

DISSOLVE

[boolean]

Default: False

If set, the result is dissolved. If no field is set for dissolving, all the buffers are dissolved into one feature.

Produce one feature for each geometry in any kind of geometry collection in the source file

EXPLODE_COLLECTIONS

[boolean]

Default: False

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

Buffer

OUTPUT

[vector: polygon]

Default: [Save to temporary file]

Specify the output buffer layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.1.2. Outputs

Label

Name

Type

Description

Buffer

OUTPUT

[vector: polygon]

The output buffer layer

23.2.7.1.3. Python code

Algorithm ID: gdal:buffervectors

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.

23.2.7.2. Clip vector by extent

Clips any OGR-supported vector file to a given extent.

This algorithm is derived from the GDAL ogr2ogr utility.

23.2.7.2.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

The input vector layer

Clip extent

EXTENT

[extent]

Defines the bounding box that should be used for the output vector file. It has to be defined in target CRS coordinates.

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

Clipped (extent)

OUTPUT

[same as input]

Default: [Save to temporary file]

Specify the output (clipped) layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.2.2. Outputs

Label

Name

Type

Description

Clipped (extent)

OUTPUT

[same as input]

The output (clipped) layer. The default format is “ESRI Shapefile”.

23.2.7.2.3. Python code

Algorithm ID: gdal:clipvectorbyextent

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.

23.2.7.3. Clip vector by mask layer

Clips any OGR-supported vector layer by a mask polygon layer.

This algorithm is derived from the GDAL ogr2ogr utility.

23.2.7.3.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

The input vector layer

Mask layer

MASK

[vector: polygon]

Layer to be used as clipping extent for the input vector layer.

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

Clipped (mask)

OUTPUT

[same as input]

Default: [Save to temporary file]

The output (masked) layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.3.2. Outputs

Label

Name

Type

Description

Clipped (mask)

OUTPUT

[same as input]

The output (masked) layer. The default format is “ESRI Shapefile”.

23.2.7.3.3. Python code

Algorithm ID: gdal:clipvectorbymasklayer

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.

23.2.7.4. Dissolve

Dissolve (combine) geometries that have the same value for a given attribute / field. The output geometries are multipart.

23.2.7.4.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: any]

The input layer to dissolve

Dissolve field

Optional

FIELD

[tablefield: any]

The field of the input layer to use for dissolving

Geometry column name

GEOMETRY

[string]

Default: ‘geometry’

The name of the input layer geometry column to use for dissolving.

Produce one feature for each geometry in any kind of geometry collection in the source file

EXPLODE_COLLECTIONS

[boolean]

Default: False

Produce one feature for each geometry in any kind of geometry collection in the source file

Keep input attributes

KEEP_ATTRIBUTES

[boolean]

Default: False

Keep all attributes from the input layer

Count dissolved features

COUNT_FEATURES

[boolean]

Default: False

Count the dissolved features and include it in the output layer.

Compute area and perimeter of dissolved features

COMPUTE_AREA

[boolean]

Default: False

Compute the area and perimeter of dissolved features and include them in the output layer

Compute min/max/sum/mean for attribute

COMPUTE_STATISTICS

[boolean]

Default: False

Calculate statistics (min, max, sum and mean) for the numeric attribute specified and include them in the output layer

Numeric attribute to calculate statistics on

Optional

STATISTICS_ATTRIBUTE

[tablefield: numeric]

The numeric attribute to calculate statistics on

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

Dissolved

OUTPUT

[same as input]

Default: [Save to temporary file]

Specify the output layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.4.2. Outputs

Label

Name

Type

Description

Dissolved

OUTPUT

[same as input]

The output multipart geometry layer (with dissolved geometries)

23.2.7.4.3. Python code

Algorithm ID: gdal:dissolve

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.

23.2.7.5. Offset curve

Offsets lines by a specified distance. Positive distances will offset lines to the left, and negative distances will offset them to the right.

23.2.7.5.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: line]

The input line layer

Geometry column name

GEOMETRY

[string]

Default: ‘geometry’

The name of the input layer geometry column to use

Offset distance (left-sided: positive, right-sided: negative)

DISTANCE

[number]

Default: 10.0

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

Offset curve

OUTPUT

[vector: line]

Default: [Save to temporary file]

Specify the output line layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.5.2. Outputs

Label

Name

Type

Description

Offset curve

OUTPUT

[vector: line]

The output offset curve layer

23.2.7.5.3. Python code

Algorithm ID: gdal:offsetcurve

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.

23.2.7.6. One side buffer

Creates a buffer on one side (right or left) of the lines in a line vector layer.

23.2.7.6.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: line]

The input line layer

Geometry column name

GEOMETRY

[string]

Default: ‘geometry’

The name of the input layer geometry column to use

Buffer distance

DISTANCE

[number]

Default: 10.0

Buffer side

BUFFER_SIDE

[enumeration]

Default: 0

One of:

  • 0 — Right

  • 1 — Left

Dissolve by attribute

Optional

FIELD

[tablefield: any]

Default: None

Field to use for dissolving

Dissolve all results

DISSOLVE

[boolean]

Default: False

If set, the result is dissolved. If no field is set for dissolving, all the buffers are dissolved into one feature.

Produce one feature for each geometry in any kind of geometry collection in the source file

EXPLODE_COLLECTIONS

[boolean]

Default: False

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

One-sided buffer

OUTPUT

[vector: polygon]

Default: [Save to temporary file]

Specify the output buffer layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.6.2. Outputs

Label

Name

Type

Description

One-sided buffer

OUTPUT

[vector: polygon]

The output buffer layer

23.2.7.6.3. Python code

Algorithm ID: gdal:onesidebuffer

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.

23.2.7.7. Points along lines

Generates a point on each line of a line vector layer at a distance from start. The distance is provided as a fraction of the line length.

23.2.7.7.1. Parameters

Label

Name

Type

Description

Input layer

INPUT

[vector: line]

The input line layer

Geometry column name

GEOMETRY

[string]

Default: ‘geometry’

The name of the input layer geometry column to use

Distance from line start represented as a fraction of line length

DISTANCE

[number]

Default: 0.5 (middle of the line)

Additional creation options

Optional

OPTIONS

[string]

Default: ‘’ (no additional options)

Additional GDAL creation options.

Points along line

OUTPUT

[vector: point]

Default: [Save to temporary file]

Specify the output point layer. One of:

  • Save to a Temporary File

  • Save to File…

The file encoding can also be changed here.

23.2.7.7.2. Outputs

Label

Name

Type

Description

Points along line

OUTPUT

[vector: point]

The output point layer

23.2.7.7.3. Python code

Algorithm ID: gdal:pointsalonglines

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.