Vector overlay

Clip

Clips a vector layer using the features of an additional polygon layer.

Only the parts of the features in the input layer that fall within the polygons of the overlay layer will be added to the resulting layer.

Warning

Feature modification

The attributes of the features are not modified, although properties such as area or length of the features will be modified by the clipping operation. If such properties are stored as attributes, those attributes will have to be manually updated.

This algorithm uses spatial indexes on the providers, prepared geometries and apply a clipping operation if the geometry isn’t wholly contained by the mask geometry.

../../../../_images/clip4.png

Clipping operation between a two-features input layer and a single feature overlay layer (left) - resulting features are moved for clarity (right)

checkbox Allows features in-place modification

Default menu: Vector ‣ Geoprocessing Tools

See also

Intersection

Parameters

Label Name Type Description
Input layer INPUT [vector: any] Layer containing the features to be clipped
Overlay layer OVERLAY [vector: polygon] Layer containing the clipping features
Clipped OUTPUT

[vector: any]

Default: [Create temporary layer]

Specify the layer to contain the features from the input layer that are inside the overlay (clipping) layer. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Clipped OUTPUT [vector: any] Layer containing features from the input layer split by the overlay layer.

Difference

Extracts features from the input layer that don’t fall within the boundaries of the overlay layer.

Input layer features that partially overlap the overlay layer feature(s) are split along the boundary of those feature(s) and only the portions outside the overlay layer features are retained.

Attributes are not modified (see warning).

../../../../_images/difference1.png

Difference operation between a two-features input layer and a single feature overlay layer (left) - resulting features are moved for clarity (right)

checkbox Allows features in-place modification

Default menu: Vector ‣ Geoprocessing Tools

Parameters

Label Name Type Description
Input layer INPUT [vector: any] Layer to extract (parts of) features from.
Overlay layer OVERLAY [vector: polygon] Layer containing the geometries that will be subtracted from the iniput layer geometries.
Difference OUTPUT

[vector: any]

Default: [Create temporary layer]

Specify the layer to contain the (parts of) features from the input layer that are not inside the overlay layer. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Difference OUTPUT [vector: any] Layer containing (parts of) features from the input layer not overlapping the overlay layer.

Extract/clip by extent

Creates a new vector layer that only contains features which fall within a specified extent.

Any features which intersect the extent will be included.

Parameters

Label Name Type Description
Input layer INPUT [vector: any] Layer to extract (parts of) features from.
Extent (xmin, xmax, ymin, ymax) OVERLAY [extent] Extent for clipping.
Clip features to extent CLIP

[boolean]

Default: False

If checked, output geometries will be automatically converted to multi geometries to ensure uniform output types. Moreover the geometries will be clipped to the extent chosen instead of taking the whole geometry as output.
Extracted OUTPUT

[vector: any]

Default: [Create temporary layer]

Specify the layer to contain the features from the input layer that are inside the clip extent. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Extracted OUTPUT [vector: any] Layer containing the clipped features.

Intersection

Extracts the portions of features from the input layer that overlap features in the overlay layer.

Features in the intersection layer are assigned the attributes of the overlapping features from both the input and overlay layers.

Attributes are not modified (see warning).

../../../../_images/intersection.png

Intersection operation between a two-features input layer and a single feature overlay layer (left) - resulting features are moved for clarity (right)

Default menu: Vector ‣ Geoprocessing Tools

See also

Clip

Parameters

Label Name Type Description
Input layer INPUT [vector: any] Layer to extract (parts of) features from.
Overlay layer OVERLAY [vector: any] Layer containing the features to check for overlap.

Input fields to keep (leave empty to keep all fields)

Optional

INPUT_FIELDS

[tablefield: any] [list]

Default: None

Field(s) of the input layer to keep in the output. If no fields are chosen all fields are taken.

Overlay fields to keep (leave empty to keep all fields)

Optional

OVERLAY_FIELDS

[tablefield: any] [list]

Default: None

Field(s) of the overlay layer to keep in the output. If no fields are chosen all fields are taken.
Intersection OUTPUT

[vector: any]

Default: [Create temporary layer]

Specify the layer to contain (the parts of) the features from the input layer that overlap one or more features from the overlay layer. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Intersection OUTPUT [vector: any] Layer containing (parts of) features from the input layer that overlap the overlay layer.

Line intersections

Creates point features where the lines from both layers intersect.

../../../../_images/line_intersection.png

Points of intersection

Default menu: Vector ‣ Analysis Tools

Parameters

Label Name Type Description
Input layer INPUT [vector: line] Input line layer.
Intersect layer INTERSECT [vector: line] Layer to use to find line intersections.

Input fields to keep (leave empty to keep all fields)

Optional

INPUT_FIELDS

[tablefield: any] [list]

Default: None

Field(s) of the input layer to keep in the output. If no fields are chosen all fields are taken.

Intersect fields to keep (leave empty to keep all fields)

Optional

INTERSECT_FIELDS

[tablefield: any] [list]

Default: None

Field(s) of the intersect layer to keep in the output. If no fields are chosen all fields are taken.
Intersection OUTPUT

[vector: point]

Default: [Create temporary layer]

Specify the layer to contain the intersection points of the lines from the input and overlay layers. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Intersections OUTPUT [vector: point] Point vector layer with the intersections.

Split with lines

Splits the lines or polygons in one layer using the lines in another layer to define the breaking points. Intersection between geometries in both layers are considered as split points.

Output will contain multi geometries for split features.

../../../../_images/split_with_lines.png

Split lines

checkbox Allows features in-place modification

Parameters

Label Name Type Description
Input layer INPUT [vector: line, polygon] Layer containing the lines or polygons to split.
Split layer LINES [vector: line] Line layer whose lines are used to define the breaking points.
Split OUTPUT

[vector: line, polygon]

Default: [Create temporary layer]

Specify the layer to contain the splitted (in case they are intersected by a line in the split layer) line/polygon features from the input layer. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Split OUTPUT [vector: line, polygon] Output vector layer with split lines or polygons from input layer.

Symmetrical difference

Creates a layer containing features from both the input and overlay layers but with the overlapping areas between the two layers removed.

The attribute table of the symmetrical difference layer contains attributes and fields from both the input and overlay layers.

Attributes are not modified (see warning).

../../../../_images/symmetrical_difference.png

Symmetrical difference operation between a two-features input layer and a single feature overlay layer (left) - resulting features are moved for clarity (right)

Default menu: Vector ‣ Geoprocessing Tools

See also

Difference

Parameters

Label Name Type Description
Input layer INPUT [vector: any] First layer to extract (parts of) features from.
Overlay layer OVERLAY [vector: any] Second layer to extract (parts of) features from.
Symmetrical difference OUTPUT

[vector: any]

Default: [Create temporary layer]

Specify the layer to contain (the parts of) the features from the input and overlay layers that so not overlap features from the other layer. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Symmetrical difference OUTPUT [vector: any] Layer containing (parts of) features from each layer not overlapping the other layer.

Union

Checks overlaps between features within the input layer and creates separate features for overlapping and non-overlapping parts. The area of overlap will create as many identical overlapping features as there are features that participate in that overlap.

../../../../_images/union1.png

Union operation with a single input layer of three overlapping features (left) - resulting features are moved for clarity (right)

An overlay layer can also be used, in which case features from each layer are split at their overlap with features from the other one, creating a layer containing all the portions from both input and overlay layers. The attribute table of the union layer is filled with attribute values from the respective original layer for non-overlapping features, and attribute values from both layers for overlapping features.

../../../../_images/union_with_overlay.png

Union operation between a two-features input layer and a single feature overlay layer (left) - resulting features are moved for clarity (right)

Note

For union(A,B) algorithm, if there are overlaps among geometries of layer A or among geometries of layer B, these are not resolved: you need to do union(union(A,B)) to resolve all overlaps, i.e. run single layer union(X) on the produced result X=union(A,B).

Default menu: Vector ‣ Geoprocessing Tools

Parameters

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer to split at any intersections.

Overlay layer

Optional

OVERLAY [vector: any] Layer that will be combined to the first one.
Union OUTPUT

[vector: any]

Default: [Create temporary layer]

Specify the layer to contain the (split and duplicated) features from the input layer and the overlay layer. One of:

  • Create Temporary Layer
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table…

The file encoding can also be changed here.

Outputs

Label Name Type Description
Union OUTPUT [vector: any] Layer containing all the overlapping and non-overlapping parts from the processed layer(s).