Géométrie vectorielle

Ajouter les attributs de géométrie

Computes geometric properties of the features in a vector layer and includes them in the output layer.

Génère une nouvelle couche vectorielle avec le même contenu que la couche d’entrée, mais avec des attributs supplémentaires, contenant des mesures géométriques basées sur un CRS sélectionné.

Les attributs ajoutés à la table dépendent du type de géométrie et de la dimension de la couche d’entrée :

  • for point layers: X (xcoord), Y (ycoord), Z (zcoord) coordinates and/or M value (mvalue)
  • for line layers: length and, for the LineString and CompoundCurve geometry types, the feature sinuosity and straight distance (straightdis)
  • for polygon layers: perimeter and area

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer
Calculate using CALC_METHOD

[enumeration]

Default: 0

Calculation parameters to use for the geometric properties. One of:

  • 0 — Le SCR de la couche
  • 1 — Le SCR du projet
  • 2 — Ellipsoïde
Added geom info OUTPUT

[same as input]

Default: [Create temporary layer]

Specify the output (input copy with geometry) layer One of:

  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Added geom info OUTPUT [same as input] Copy of the input vector layer with the addition of the geometry fields

Agrégation

Créé une nouvelle couche en agrégeant les entités selon une expression de regroupement ( « group by » )

Les entités pour lesquelles l’agrégation retourne la même valeur sont regroupées.

Il est possible de regrouper toutes les entités en utilisant une valeur constante dans le « group by ». Par exemple : NULL

Il est aussi possible de regrouper suivant plusieurs champs à l’aide de fonctions Array, comme Array (« Colonne1 », « Colonne2 »).

Les géométries (lorsqu’elles sont présentes) sont agrégées en multi-géométries pour chaque groupe. Les attributs sont calculés avec une fonction d’agrégation propre à chacun.

This algorithm allows to use the default aggregates functions of the QGIS Expression engine.

Paramètres

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer
Group by expression GROUP_BY

[tablefield: any]

Default: “NULL”

Choose the grouping field. If NULL all features will be grouped
Aggregates AGGREGATES [list]

List of output layer field definitions. Example of a field definition:

{“aggregate”: “sum”, “delimiter”: “,”, “input”: “ $area”, “length”: 10, “name”: “totarea”, “precision”: 0, “type”: 6}

By default, the list contains all the fields of the input layer. In the GUI, you can edit these fields and their definitions, and you can also:

  • Click the newAttribute button to add a new field.
  • Click deleteAttribute to delete the selected field.
  • Use arrowUp and arrowDown to change order of the fields.
  • Click clearText to reset to the default (the fields of the input layer).

For each of the fields you’d like to retrieve information from, you need to define the following:

Input expression [expression] (input)
Champ ou expression de la couche en entrée.
Aggregate function [enumeration] (aggregate)

Fonction utilisable dans l’expression pour avoir la valeur agrégée.

Par défaut: concatenation (pour les champs alphanumériques “string” ), somme (pour les champs numériques)

Delimiter [string] (delimiter)

Séparateur des valeurs agrégées, par exemple pour les concaténations de champs texte.

Par défaut: ,

Output field name [string] (name)
Nom du champ agrégé dans la couche en sortie. Par défaut, le nom du champ en entrée est repris.
Type [enumeration] (type)

Data type of the output field. One of:

  • 1 — Boolean
  • 2 — Integer
  • 4 — Integer64
  • 6 — Double
  • 10 — String
  • 14 — Date
  • 16 — DateTime
Length [number] (length)
Longueur du champ en sortie.
Precision [number] (precision)
Précision du champ en sortie.
Load fields from layer GUI only [vector: any] You can load fields from another layer and use them for the aggregation
Aggregated OUTPUT

[same as input]

Default: [Create temporary layer]

Specify the output (aggregate) layer One of:

  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Aggregated OUTPUT [same as input] Multigeometry vector layer with the aggregated values

Limite

Renvoie pour chaque entité la ou les limites de celle ci (c’est-à-dire la limite topologique de la géométrie).

Only for polygon and line layers.

For polygon geometries , the boundary consists of all the lines making up the rings of the polygon.

../../../../_images/boundary_polygon.png

Boundaries (black dashed line) of the source polygon layer

Pour les géométries linéaires, les limites sont les sommets entre chaque entités.

../../../../_images/boundary_lines.png

Boundary layer (red points) for lines. In yellow a selected feature.

Paramètres

Label Name Type Description
Input layer INPUT [vector: line, polygon] Input line or polygon vector layer
Boundary OUTPUT [vector: point, line]

Specify the output (boundary) layer. One of:

  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Boundary OUTPUT [vector: point, line] Boundaries from the input layer (point for line, and line for polygon)

Emprise

Calcule le rectangle d’encombrement (emprise) pour chaque entité de la couche en entrée. Polygones et lignes sont possibles.

../../../../_images/bounding_box.png

Les lignes noires représentent les rectangles d’encombrement de chaque entité.

checkbox Permet la modification de la couche source

Paramètres

Label Name Type Description
Input layer INPUT [vector: line, polygon] Input line or polygon vector layer
Bounds OUTPUT [vector: polygon]

Specify the output (bounding box) layer. One of:

  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Bounds OUTPUT [vector: polygon] Bounding boxes of input layer

Tampon

Crée un tampon de largeur fixe pour chaque entité de la couche.

Il est possible d’utiliser une largeur négative pour les polygones de la couche en entrée: dans ce cas, le tampon est un polygone moins large.

../../../../_images/buffer2.png

En jaune, les tampons des points, lignes et polygones.

checkbox Permet la modification de la couche source

Menu par défaut: Vecteur ‣ Outils de géotraitement

Paramètres

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer
Distance DISTANCE

[number dataDefined]

Default: 10.0

Buffer distance (from the boundary of each feature). You can use the Data Defined button on the right to choose a field from which the radius will be calculated. This way you can have different radius for each feature (see Variable distance buffer (Processing Modeler only)).
Segments SEGMENTS

[number]

Default: 5

Indique le nombre de segments de ligne à utiliser pour approcher un quart de cercle lors de la création de tampons arrondis
End cap style END_CAP_STYLE

[enumeration]

Default: 0

Controls how line endings are handled in the buffer. One of:

  • 0 — Rond
  • 1 — Plat
  • 2 — Carré
../../../../_images/buffer_cap_style.png

Style de terminaison rond, plat et carré

Join style JOIN_STYLE

[enumeration]

Par défaut : 0

Indique si les joints ronds, à angles droits ou biseautés doivent être utilisés lors du décalage des coins dans une ligne. Les options sont :

  • 0 — Rond
  • 1 — Angle droit
  • 2 — Oblique
Miter limit MITER_LIMIT

[number]

Default: 2.0

Controls the maximum distance from the offset curve to use when creating a mitered join (only applicable for miter join styles). Minimum: 1.
Dissolve result DISSOLVE

[boolean]

Default: False

Dissolve the final buffer. If True (checked), overlapping buffers will be dissolved (combined) into a new feature.

../../../../_images/buffer_dissolve1.png

Tampon standard (gauche) et tampon fusionné (droite)

Buffered OUTPUT [vector: polygon]

Specify the output (buffer) layer. One of:

  • Skip output
  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Buffered OUTPUT [vector: polygon] Output (buffer) polygon layer

Centroïdes

Creates a new point layer, with points representing the centroids of the geometries of the input layer.

Le centroïde résultant peut être un unique point représentant le barycentre (de toutes les parties) de l’entité, il peut par conséquent se trouver en dehors des limites de l’entité. Le résultat peut aussi correspondre à un point pour chaque partie de l’entité.

Cet algorithme créé un nouvelle couche de type point, ou les points représentent le barycentre des entités d’une couche d’entrée.

../../../../_images/centroids2.png

Les étoiles rouges représentent le centroïde de chaque entité de la couche d’entrée.

checkbox Permet la modification de la couche source

Menu par défaut: Vecteur ‣ Outils de géométrie

Voir aussi

Point on surface

Paramètres

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer
Create centroid for each part ALL_PARTS

[boolean dataDefined]

Default: False

If True (checked), a centroid will be created for each part of the geometry
Centroids OUTPUT [vector: point]

Specify the output (centroid) layer. One of:

  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Centroids OUTPUT [vector: point] Output point vector layer (centroids)

Vérifier la validité

Effectue un contrôle de validité sur les géométries d’une couche vectorielle.

The geometries are classified in three groups (valid, invalid and error) and for each group, a vector layer with its features is generated:

  • The Valid output layer contains only the valid features (without topological errors).
  • The Invalid output layer contains all the invalid features found by the algorithm.
  • The Error output layer is a point layer that points to where the invalid features were found.

The attribute tables of the generated layers will contain some additional information (« message » for the error layer, « FID » and « _errors » for the invalid layer and only « FID » for the valid layer):

The attribute table of each generated vector layer will contain some additional information (number of errors found and types of error):

../../../../_images/check_validity.png

Left: the input layer. Right: the valid layer (green), the invalid layer (orange)

Menu par défaut: Vecteur ‣ Outils de géométrie

Voir aussi

Fix geometries

Paramètres

Label Name Type Description
Input layer INPUT_LAYER [vector: any] Input vector layer
Method METHOD

[enumeration]

Default: 2

Method to use to check validity. Options:

  • 0: The one selected in digitizing settings
  • 1: QGIS
  • 2: GEOS
Ignore ring self intersection IGNORE_RING_SELF_INTERSECTION

[boolean]

Default: False

Ignore self intersecting rings when checking for validity.
Valid output VALID_OUTPUT

[same as input]

Default: [Create temporary layer]

Specify the vector layer to contain a copy of the valid features of the source layer. One of:

  • Skip output
  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Invalid output INVALID_OUTPUT

[same as input]

Default: [Create temporary layer]

Vector layer containing copy of the invalid features of the source layer with the field _errors listing the summary of the error(s) found. One of:

  • Skip output
  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Error output ERROR_OUTPUT

[vector: point]

Default: [Create temporary layer]

Point layer of the exact position of the validity problems detected with the message field describing the error(s) found. One of:

  • Skip output
  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Sorties

Label Name Type Description
Count of errors ERROR_COUNT [number] The number of geometries that caused errors.
Error output ERROR_OUTPUT [vector: point] Couche de points des positions exactes des problèmes de validité détectés avec le champ ``message``décrivant la ou les erreur(s) trouvée(s).
Count of invalid features INVALID_COUNT [number] The number of invalid geometries.
Invalid output INVALID_OUTPUT [same as input] Vector layer containing copy of the invalid features of the source layer with the field _errors listing the summary of the error(s) found.
Count of valid features VALID_COUNT [number] The number of valid geometries.
Valid output VALID_OUTPUT [same as input] Vector layer containing a copy of the valid features of the source layer.

Type of error messages and their meanings

If the GEOS method is used the following error messages can occur:
Message error Explanation Example
Repeated point This error happens when a given vertex is repeated.
../../../../_images/geos_rep_point.png
Ring self-intersection This error happens when a geometry touches itself and generates a ring.
../../../../_images/geos_ring_inter.png
Self-intersection This error happens when a geometry touches itself.
../../../../_images/geos_self_inter.png
Topology validation error    
Hole lies outside shell    
Holes are nested    
Interior is disconnected    
Nested shells This error happens when a polygon geometry is on top of another polygon geometry.
../../../../_images/geos_nest_shell.png
Duplicate rings    
Too few points in geometry component    
Invalid coordinate    
Ring is not closed    
If the QGIS method is used the following error messages can occur:
Message error Explanation Example
Segment %1 of ring %2 of polygon %3 intersects segment %4 of ring %5 of polygon %6 at %7    
Ring %1 with less than four points    
Ring %1 not closed    
Line %1 with less than two points    
Line %1 contains %n duplicate node(s) at %2    
Segments %1 and %2 of line %3 intersect at %4    
Ring self-intersection    
Ring %1 of polygon %2 not in exterior ring    
Polygon %1 lies inside polygon %2 This error happens when a part of MultiPolygon geometry is inside a hole of a MultiPolygon geometry.
../../../../_images/qgis_poliinside_.png

Collecter les géométries

Prend une couche vectorielle et réunit ses géométries dans de nouvelles géométries multiparties.

Un ou plusieurs attributs peuvent être spécifiés pour collecter uniquement des géométries appartenant à la même classe (ayant la même valeur pour les attributs spécifiés), en variante, toutes les géométries peuvent être collectées.

Toutes les géométries de sortie seront converties en géométries multiples, même celles avec une seule partie. Cet algorithme ne dissout pas les géométries se chevauchant - elles seront rassemblées sans modifier la forme de chaque partie géométrique.

Voir les algorithmes «Convertir en multiparties» ou «Agrégat» pour des options alternatives.

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer
Unique ID fields FIELD [tablefield: any] [list] Choose one or more attributes to collect the geometries
Collected OUTPUT [same as input] Vector layer with collected geometries

Sorties

Label Name Type Description
Collected OUTPUT

[same as input]

Default: [Create temporary layer]

Specify the output vector layer for the collected geometries. One of:

  • Create Temporary Layer (TEMPORARY_OUTPUT)
  • Save to File…
  • Save to Geopackage…
  • Save to PostGIS Table

The file encoding can also be changed here.

Enveloppe concave (formes alpha)

Calcule l’enveloppe convexe des entités dans une couche de points en entrée.

Paramètres

Couche de point en entrée [vecteur : point]
Couche de points vectorielle pour calculer l’enveloppe concave.
Seuil [nombre]

Nombre de 0 (enveloppe concave maximum) à 1 (enveloppe convexe)

Par défaut : 0.3

../../../../_images/concave_hull_threshold.png

Différents seuils utilisés (0.3, 0.6, 0.9)

Autoriser les trous [booléen]

Choisir si les trous sont autorisés dans l’enveloppe concave finale.

Par défaut : Vrai

Séparer la géométrie multipartie en géométries simples [booléen]

Cocher si vous voulez obtenir des géométries simples à la place des multiparties.

Par défaut : Faux

Sorties

Enveloppe concave [vecteur: polygone]
Sortie de l’enveloppe concave.

Enveloppe concave (voisin le plus proche)

Cet algorithme génère un polygone formant une enveloppe concave autour d’une série de points. Si la couche en entrée est une couche de ligne ou de polygone, il utilisera les sommets.

Le nombre de voisins à considérer détermine la concavité du polygone de sortie. Un chiffre plus bas donnera un polygone concave qui suit les points de très près, tandis qu’un chiffre plus élevé donnera une forme plus lisse. Le nombre minimum de points voisins à considérer est de 3. Une valeur égale ou supérieure au nombre de points donnera un polygone convexe.

Si un champ est sélectionné, l’algorithme regroupera les entités de la couche d’entrée ayant des valeurs uniques dans ce champ et générera des polygones individuels dans la couche de sortie pour chaque groupe.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle pour calculer l’enveloppe concave.
Nombre de points voisins à considérer [nombre]

Détermine la concavité du polygone de sortie. Un chiffre plus bas donnera un polygone concave qui suit les points de très près, tandis qu’un chiffre plus élevé aboutira à un polygone plus proche d’une enveloppe convexe (si le nombre est égal ou supérieur au nombre d’entités, le résultat sera un polygone convexe).

Par défaut (et minimum) : 3

Champ [champ : n’importe lequel]

Optionnel

Si spécifié, un polygone concave est généré pour chaque valeur unique du champ (en sélectionnant les entités utilisant cette valeur).

Par défaut : Aucun

Sorties

Enveloppe concave [vecteur: polygone]
Sortie de l’enveloppe concave.

Convertir le type de géométrie

Génère une nouvelle couche basée sur une couche existante, avec un type de géométrie différent.

Toutes les conversions ne sont pas possibles. Par exemple, une couche de lignes peut être convertie en couche de points, mais une couche de points ne peut pas être convertie en une couche de lignes.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée à transformer.
Nouveau type de géométrie [énumération]

Type de géométrie à appliquer aux entités de sortie. Les options sont:

  • 0 — Centroïdes
  • 1 — Noeuds
  • 2 — Polylignes
  • 3 — Multi-lignes
  • 4 — Polygones

Note

Les types de conversion disponibles dépendent de la couche en entrée et de la conversion choisie: par exemple il n’est pas possible de convertir des points en lignes.

Sorties

Converti [vecteur : n’importe lequel]
Couche vectorielle convertie dépendant des paramètres choisis.

Enveloppe convexe

Calcule l’enveloppe convexe pour chaque entité dans une couche en entrée.

Voir l’algorithme “Géométrie de délimitation minimale” pour un calcul d’enveloppe convexe qui couvre la totalité de la couche ou des sous-ensembles groupés d’entités.

../../../../_images/convex_hull1.png

Les lignes noires représentent les enveloppes convexes de chaque entité.

checkbox Permet la modification de la couche source

Menu par défaut: Vecteur ‣ Outils de géotraitement

Paramètres

Couche de points en entrée [vecteur: n’importe lequel]
Couche de points vectorielle pour calculer l’enveloppe convexe.

Sorties

Enveloppe convexe [vecteur: polygone]
Enveloppe convexe en sortie.

Create layer from extent

Creates a new vector layer that contains a single feature with geometry matching the extent of the input layer.

It can be used in models to convert a literal extent (xmin, xmax, ymin, ymax format) into a layer which can be used for other algorithms which require a layer based input.

Paramètres

Extent (xmin, xmax, ymin, ymax) [extent]
Extent to represent.

Sorties

Extent
Layer with a polygon feature representing the input extent.

Create wedge buffers

Creates wedge shaped buffers from input points.

../../../../_images/wedge_buffers.png

Wedge buffers

The native output from this algorithm are CurvePolygon geometries, but these may be automatically segmentized to Polygons depending on the output format.

Paramètres

Input layer [vector: point]
Input point vector layer.
Azimuth (degrees from North) [number dataDefined]
Angle (in degrees) as the middle value of the wedge.
Wedge width (in degrees) [number dataDefined]

Width (in degrees) of the buffer. The wedge will extend to half of the angular width either side of the azimuth direction.

../../../../_images/wedge_buffers_azimuth_width.png

Azimuth and width values of the wedge buffer

Outer radius [number dataDefined]
The outer size (length) of the wedge: the size is meant from the source point to the edge of the wedge shape.
Inner radius [number dataDefined]

Optionnel

Inner radius value. If 0 the wedge will begin from the source point.

Default: 0.0

Sorties

Buffers [vector: polygon]
Wedge buffer polygon vector layer.

Delaunay triangulation

Creates a polygon layer with the delaunay triangulation corresponding to a point layer.

../../../../_images/delaunay1.png

Delaunay triangulation on points

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Input layer [vector: point]
Point vector layer to compute the triangulation on.

Sorties

Delaunay triangulation [vector: polygon]
Resulting polygon layer of delaunay triangulation.

Delete holes

Takes a polygon layer and removes holes in polygons. It creates a new vector layer in which polygons with holes have been replaced by polygons with only their external ring. Attributes are not modified.

An optional minimum area parameter allows removing only holes which are smaller than a specified area threshold. Leaving this parameter at 0.0 results in all holes being removed.

../../../../_images/delete_holes.png

Before and after the cleaning

checkbox Permet la modification de la couche source

Paramètres

Input layer [vector: polygon]
Polygon layer with holes.
Remove holes with area less than [number dataDefined]

Optionnel

Only holes with an area less than this threshold will be deleted. If 0.0 is added, all the holes will be deleted.

Default: 0.0

Sorties

Cleaned [vector: polygon]
Vector layer without holes or holes larger than specified area.

Densify by count

Takes a polygon or line layer and generates a new one in which the geometries have a larger number of vertices than the original one.

If the geometries have Z or M values present then these will be linearly interpolated at the added vertices.

The number of new vertices to add to each segment is specified as an input parameter.

../../../../_images/densify_geometry.png

Red points show the vertices before and after the densify

checkbox Permet la modification de la couche source

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Polygon or line vector layer to densify.
Vertices to add [number]

Number of vertices to add to each segment.

Default: 1

Sorties

Densified [vector: line, polygon]
Densified layer with vertices added.

Voir également

Densify by interval

Densify by interval

Takes a polygon or line layer and generates a new one in which the geometries have a larger number of vertices than the original one.

The geometries are densified by adding regularly placed extra vertices inside each segment so that the maximum distance between any two vertices does not exceed the specified distance.

If the geometries have Z or M values present then these will be linearly interpolated at the added vertices.

Example

Specifying a distance 3 would cause the segment [0 0] -> [10 0] to be converted to [0 0] -> [2.5 0] -> [5 0] -> [7.5 0] -> [10 0], since 3 extra vertices are required on the segment and spacing these at 2.5 increments allows them to be evenly spaced over the segment.

../../../../_images/densify_geometry_interval.png

Densify geometry at a given interval

checkbox Permet la modification de la couche source

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Polygon or line vector layer to densify.
Interval between vertices to add [number]

Maximum distance between two consecutive vertices.

Default: 1.0

Sorties

Densified [vector: line, polygon]
Densified layer with vertices added using the specified interval.

Voir également

Densify by count

Regrouper

Prend une couche vectorielle et combine ses entités en nouvelles entités. Un ou plusieurs champs peuvent être spécifiés pour dissoudre les entités appartenant à la même classe (ayant la même valeur pour les champs spécifiés), autrement toutes les entités seront dissoutes en une unique entité.

Toutes les géométries en sortie seront converties en multigéométries. Dans le cas d’une couche de polygones, les frontières communes de polygones adjacents regroupés seront supprimées.

La table attributaire résultant aura les mêmes champs que la couche d’entrée. Les valeurs des champs de la couche de sortie seront celles de la première entité en entrée qui sera traitée.

../../../../_images/dissolve1.png

Regrouper la couche de polygones sur un attribut commun

Menu par défaut: Vecteur ‣ Outils de géotraitement

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle à regrouper.
Champ(s) de regroupement [champ de table : n’importe lequel] [liste]

Optionnel

Les entités ayant la même valeur pour le ou les champ(s) spécifié(s) seront replacées par par une seule entité et leurs géométries seront fusionnées.

Si aucun champ n’est indiqué alors toutes les entités seront regroupées dans une seule entité.

Sorties

Regroupé [vecteur: n’importe lequel]
Couche de type multigéométrie avec des géométries fusionnées mais des valeurs non aggrégées dans les champs.

Drapé (régler la valeur z du raster)

Uses values sampled from a band within a raster layer to set the Z value for every overlapping vertex in the feature geometry. The raster values can optionally be scaled by a preset amount.

If Z values already exist in the layer, they will be overwritten with the new value. If no Z values exist, the geometry will be upgraded to include the Z dimension.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer to set the Z values to.
Raster layer [raster]
Raster layer to take the Z values from.
Band number [raster band]
The raster band to take the Z values from if the raster is multiband.
Value for nodata or non-intersecting vertices [number dataDefined]

Value to use in case the vertex does not intersect (a valid pixel of) the raster.

Par défaut : 0

Scale [number dataDefined]

Scaling value: the band values are multiplied by this value.

Default: 1.0

Sorties

Updated [vector: any]
A vector layer with geometries that have Z values extracted from the provided raster layer.

Drop m/z values

Removes any M (measure) or Z (altitude) values from input geometries.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer from which M and/or Z values will be dropped.
Drop M Values [boolean]

Removes the M values from the geometries.

Par défaut : Faux

Drop Z Values [boolean]

Removes the Z values from the geometries.

Par défaut : Faux

Sorties

Z/M Dropped [vector: any]
A vector layer that is identical to the input layer, except that M and/or Z values have been removed from its geometries.

Voir également

Set M value, Set Z value

Eliminate selected polygons

Combines selected polygons of the input layer with certain adjacent polygons by erasing their common boundary. The adjacent polygon can be either the one with the largest or smallest area or the one sharing the largest common boundary with the polygon to be eliminated.

Eliminate is normally used to get rid of sliver polygons, i.e. tiny polygons that are a result of polygon intersection processes where boundaries of the inputs are similar but not identical.

Menu par défaut: Vecteur ‣ Outils de géotraitement

Paramètres

Input layer [vector: polygon]
Input polygon vector layer to clean.
Merge selection with the neighboring polygon with the [enumeration]

Choose the parameter to use in order to get rid of the selected polygons:

  • Largest Area
  • Smallest Area
  • Largest Common Boundary

Sorties

Eliminated [vector: polygon]
Cleaned vector layer as result of the parameters chosen.

Explode lines

Takes a lines layer and creates a new one in which each line layer is replaced by a set of lines representing the segments in the original line.

Each line in the resulting layer contains only a start and an end point, with no intermediate vertices between them.

../../../../_images/explode_lines.png

The original line layer and the exploded one

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Paramètres

Input layer [vector: line]
Line vector layer in input to explode.

Sorties

Exploded [vector: line]
Output vector line with features representing each segment of the input layer.

Extend lines

Extends line geometry by a specified amount at the start and end of the line.

Lines are extended using the bearing of the first and last segment in the line.

../../../../_images/extend_lines.png

The red dashes represent the initial and final extension of the original layer

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Paramètres

Input layer [vector: line]
Line vector layer to extend.
Start distance [number dataDefined]
Distance by which to extend the first segment of the line (starting point).
End distance [number dataDefined]
Distance by which to extend the last segment of the line (ending point).

Sorties

Extended [vector: line]
Extended vector line layer.

Voir également

Line substring

Extract specific vertices

Takes a line or polygon layer and generates a point layer with points representing specific vertices in the input lines or polygons.

For instance, this algorithm can be used to extract the first or last vertices in the geometry. The attributes associated to each point are the same ones associated to the line or polygon that the point belongs to.

The vertex indices parameter accepts a comma separated string specifying the indices of the vertices to extract. The first vertex corresponds to an index of 0, the second vertex has an index of 1, etc. Negative indices can be used to find vertices at the end of the geometry, e.g., an index of -1 corresponds to the last vertex, -2 corresponds to the second last vertex, etc.

Additional fields are added to the vertices indicating the specific vertex position (e.g., 0, -1, etc), the original vertex index, the vertex’s part and its index within the part (as well as its ring for polygons), distance along the original geometry and bisector angle of vertex for the original geometry.

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Vector layer in input to extract the vertices from.
Vertex indices [number]

Type the indices of the vertices to extract. The algorithm accepts comma separated values for many vertices to extract (e.g. -2, 3, 5, 7).

Par défaut : 0

Sorties

Vertices [vector: point]
Point layer with features representing the specific vertices in the input layer.

Extract vertices

Takes a line or polygon layer and generates a point layer with points representing the vertices in the input lines or polygons.

The attributes associated to each point are the same ones associated to the line or polygon that the point belongs to.

Additional fields are added to the vertices indicating the vertex index (beginning at 0), the feature’s part and its index within the part (as well as its ring for polygons), distance along original geometry and bisector angle of vertex for original geometry.

../../../../_images/extract_nodes1.png

Vertices extracted for line and polygon layer

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Vector layer in input to extract the vertices from.

Sorties

Vertices [vector: point]
Point layer with features representing all the vertices in the input layer.

Filter vertices by M value

Filters away vertices based on their M value, returning geometries with only vertex points that have a M value greater than or equal to the specified minimum value and/or less than or equal to the maximum value.

If the minimum value is not specified then only the maximum value is tested, and similarly if the maximum value is not specified then only the minimum value is tested.

../../../../_images/filter_zm.png

The red line represents the black line with only vertices whose M value is <=10.

Note

Depending on the input geometry attributes and the filters used, the resultant geometries created by this algorithm may no longer be valid.

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Vector layer to remove vertices from.
Minimum [number dataDefined]

Optionnel

Minimum M value allowed to keep a vertex.

Default: Not set

Maximum [number dataDefined]

Optionnel

Maximum M value allowed to keep a vertex.

Default: Not set

Sorties

Filtered [vector: line, polygon]
Vector layer of the features with only the filtered vertices.

Filter vertices by Z value

Filters away vertices based on their Z value, returning geometries with only vertex points that have a Z value greater than or equal to the specified minimum value and/or less than or equal to the maximum value.

If the minimum value is not specified then only the maximum value is tested, and similarly if the maximum value is not specified then only the minimum value is tested.

../../../../_images/filter_zm.png

The red line represents the black line with only vertices whose Z value is <=10.

Note

Depending on the input geometry attributes and the filters used, the resultant geometries created by this algorithm may no longer be valid. You may need to run the Fix geometries algorithm to ensure their validity.

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Vector layer to remove vertices from.
Minimum [number dataDefined]

Optionnel

Minimum Z value allowed to keep a vertex.

Default: Not set

Maximum [number dataDefined]

Optionnel

Maximum Z value allowed to keep a vertex.

Default: Not set

Sorties

Filtered [vector: line, polygon]
Vector layer of the features with only the filtered vertices.

Fix geometries

Attempts to create a valid representation of a given invalid geometry without losing any of the input vertices. Already valid geometries are returned without further intervention. Always outputs multi-geometry layer.

Note

M values will be dropped from the output.

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Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Polygon or vector layer in input.

Sorties

Fixed geometries [vector: line, polygon]
Layer with fixed geometries.

Geometry by expression

Updates existing geometries (or creates new geometries) for input features by use of a QGIS expression.

This allows complex geometry modifications which can utilize all the flexibility of the QGIS expression engine to manipulate and create geometries for output features.

For help with QGIS expression functions, see the inbuilt help for specific functions which is available in the expression builder.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Vector input layer.
Output geometry type [enumeration]

The output geometry strongly depends on the expression you will choose: for instance, if you want to create a buffer then the geometry type has to be a polygon.

Available options are:

  • 0 — Polygon
  • 1 — Line
  • 2 — Point

Par défaut : 0

Output geometry has z dimension [boolean]

Choose if the output geometry should have the Z dimension.

Par défaut : Faux

Output geometry has m values [boolean]

Choose if the output geometry should have the M dimension.

Par défaut : Faux

Geometry expression [expression]

Add the geometry expression you want to use. You can use the button to open the Expression Dialog: the dialog has a list of all the usable expression together with their help and guide.

Default: $geometry

Sorties

Modified geometry [vector: any]
Vector layer resulting from the expression added.

Interpolate point on line

Creates a point geometry interpolated at a set distance along line or curve geometries.

Z and M values are linearly interpolated from existing values.

If a multipart geometry is encountered, only the first part is considered when calculating the substring.

If the specified distance is greater than the input feature’s length, the resultant feature will have a null geometry.

../../../../_images/interpolated_point.png

Interpolated point at 500m of the beginning of the line

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Line or polygon vector layer from which to interpolate point placement.
Distance [nombre dataDefined]
Distance from the beginning of the line.

Sorties

Interpolated points [vector: point]
Point vector layer with features at a set distance along the line or polygon boundary.

Voir également

Points along geometry

Keep n biggest parts

Takes a layer with polygons or multipolygons and returns a new layer in which only the n largest polygons of each multipolygon feature are kept. If a feature has n or fewer parts, the feature will just be copied.

../../../../_images/n_biggest.png

Clockwise from left-up: original multipart feature, one, two and three biggest parts kept

Paramètres

Polygons [vector: polygon]
Input polygon layer.
To keep [number]

Choose how many parts to keep. If 1 is selected, only the biggest part of the feature will be kept.

Default: 1

Sorties

Biggest parts [vector: polygon]
Resulting polygon layer with the n biggest parts of each feature.

Line substring

Returns the portion of a line (or curve) which falls between the specified start and end distances (measured from the beginning of the line).

Z and M values are linearly interpolated from existing values.

If a multipart geometry is encountered, only the first part is considered when calculating the substring.

../../../../_images/substring.png

Substring line with starting distance set at 0 meters and the ending distance at 250 meters.

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Paramètres

Input layer [vector: line]
Line vector layer to extract the substring from.
Start distance [number dataDefined]
Distance along the input line, representing the start point of the output feature.
End distance [number dataDefined]
Distance along the input line, representing the end point of the output feature.

Sorties

Substring [vector: line]
Vector line layer of the substring

Voir également

Extend lines

Lines to polygon

Generates a polygon layer using as polygon rings the lines from an input line layer.

The attribute table of the output layer is the same as the one from of the input line layer.

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Input layer [vector: line]
Line vector layer to convert.

Sorties

Polygons [vector: polygon]
Polygon vector layer from the line input vector layer.

Merge lines

Joins all connected parts of MultiLineString geometries into single LineString geometries.

If any parts of the input MultiLineString geometries are not connected, the resultant geometry will be a MultiLineString containing any lines which could be merged and any non-connected line parts.

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Paramètres

Input layer [vector: line]
MultiLineString vector layer.

Sorties

Merged [vector: lines]
Single LineString vector layer.

Minimum bounding geometry

Creates geometries which enclose the features from an input layer.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Champ [champ : n’importe lequel]

Optionnel

Features can be grouped by a field. If set, this causes the output layer to contain one feature per grouped value with a minimal geometry covering only the features with matching values.

Geometry type [enumeration]

Numerous enclosing geometry types are supported:

  • 0 — Envelope (Bounding Box)
  • 1 — Minimum Oriented Rectangle
  • 2 — Minimum Enclosing Circle
  • 3 — Convex Hull

Par défaut : 0

../../../../_images/minimum_bounding.png

Clockwise from left-up: envelopes, oriented rectangle, circle, convex hull

Sorties

Bounding geometry [vector: polygon]
Bounding polygon layer.

Minimum enclosing circles

Calculates the minimum enclosing circle which covers each feature in an input layer.

../../../../_images/minimum_enclosing_circles.png

Enclosing circles for each feature

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Number of segment in circles [number]

Choose the number of segment for each circle.

Default: 72

Sorties

Minimum enclosing circles [vector: polygon]
Enclosing circles for each polygon feature.

Voir également

Minimum bounding geometry

Multi-ring buffer (constant distance)

Computes multi-ring (donuts) buffer for all the features in an input layer, using a fixed or dynamic distance and ring numbers.

../../../../_images/multiringbuffer.png

Multi-ring buffer for line, point and polygon layer

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Number of rings [number dataDefined]
Total number of rings that the buffer must have. It can be a unique value (same ring number for all the features) or it can be taken from features data (different ring number depending on the feature values).
Distance between rings [number dataDefined]
Distance between the single rings. It can be a unique value (same distance for all the features) or it can be taken from features data (different distance depending on the feature values).

Sorties

Multi-ring buffer (constant distance)
Multi ring buffer polygon vector layer.

Multipart to singleparts

Splits the multipart input layers into single features.

The attributes of the output layers are the same of the original ones but divided into single features.

../../../../_images/multipart.png

Left the multipart source layer and right the single part output result

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Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Multipart input layer.

Sorties

Single parts [vector: any]
Singlepart layer in output with updated attribute table.

Offset lines

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

../../../../_images/offset_lines.png

In blue the source layer, in red the offset one

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Paramètres

Input layer [vector: line]
Line vector layer in input to elaborate the offset on.
Distance [nombre dataDefined]

Distance of the offset.

Défaut: 10.0

Segment [number]

Number of line segments to use to approximate a quarter circle when creating rounded offsets.

Default: 8

Style de jointure [énumération]

Specify whether round, miter or beveled joins should be used when offsetting corners in a line. Options are:

  • 0 — Rond
  • 1 — Angle droit
  • 2 — Oblique

Par défaut : 0

Limite d'angle droit [nombre]

Only applicable for mitered join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.

Par défaut : 2.0

Sorties

Offset [vector: line]
Offset line layer.

Oriented minimum bounding box

Calculates the minimum area rotated rectangle which covers each feature in an input layer.

../../../../_images/oriented_minimum_bounding_box.png

Oriented minimum bounding box

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.

Sorties

Bounding boxes [vector: polygon]
Oriented minimum bounding boxes for each polygon feature.

Voir également

Minimum bounding geometry

Orthogonalize

Takes a line or polygon layer and attempts to orthogonalize all the geometries in the layer. This process shifts the vertices in the geometries to try to make every angle in the geometry either a right angle or a straight line.

../../../../_images/orthogonize.png

In blue the source layer while the red line is the orthogonalized result

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Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Couche vectorielle en entrée.
Maximum angle tolerance (degrees) [number]
Specify the maximum deviation from a right angle or straight line a vertex can have for it to be adjusted. Smaller tolerances mean that only vertices which are already closer to right angles will be adjusted, and larger tolerances mean that vertices which deviate further from right angles will also be adjusted.
Maximum algorithm iterations [number]
Setting a larger number for the maximum iterations will result in a more orthogonal geometry at the cost of extra processing time.

Sorties

Orthogonalized [vector: line, polygon]
Final layer with angles adjusted depending on the parameters chosen.

Point on surface

Returns a point guaranteed to lie on the surface of a geometry.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Créer un point sur la surface pour chaque partie [booléen dataDefined]

Si coché, un point sera créé pour chaque partie différente de la géométrie.

Par défaut : Faux

Sorties

Point [vector: point]
Point vector layer.

Voir également

Centroïdes

Points along geometry

Creates points at regular intervals along line or polygon geometries. Created points will have new attributes added for the distance along the geometry and the angle of the line at the point.

An optional start and end offset can be specified, which controls how far from the start and end of the geometry the points should be created.

../../../../_images/points_along_line.png

Points created along the source line layer

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Couche vectorielle en entrée.
Distance [number]

Distance between two consecutive points along a geometry.

Default: 100

Start offset [number]

Distance from the beginning of the input line, representing the position of the first point.

Par défaut : 0

End offset [number]

Distance from the end of the input line, representing the position beyond which no point feature shoud be created.

Par défaut : 0

Sorties

Points [vector: point]
Point vector layer with features placed along the line or polygon boundary.

Voir également

Interpolate point on line

Points displacement

Given a distance of proximity, identifies nearby point features and radially distributes them over a circle whose center represents their barycenter. A convenient tool to scatter overlaid features.

Paramètres

Input layer [vector: point]
Input point vector layer.
Minimum distance to other points [number]

Distance below which point features are considered close. Close features are distributed altogether.

Default: 1.0

Displacement distance [number]

Radius of the circle on which close features are placed.

Default: 1.0

Horizontal distribution for two point case [boolean]

When only two points are identified as close, aligns them horizontally on the circle instead of vertically.

Par défaut : Faux

Sorties

Displaced [vector: point]
Point vector layer with displaced features.

Pole of inaccessibility

Calculates the pole of inaccessibility for a polygon layer, which is the most distant internal point from the boundary of the surface.

This algorithm uses the “polylabel” algorithm (Vladimir Agafonkin, 2016), which is an iterative approach guaranteed to find the true pole of inaccessibility within a specified tolerance. A more precise tolerance (lower value) requires more iterations and will take longer to calculate.

The distance from the calculated pole to the polygon boundary will be stored as a new attribute in the output layer.

../../../../_images/pole_inaccessibility.png

Pole of inaccessibility

Paramètres

Input layer [vector: polygon]
Input polygon vector layer.
Tolerance [number]

Set the tolerance for the calculation.

Default: 1.0

Sorties

Point [vector: point]
Point as pole of inaccessibility for the source polygon vector layer.

Transformer en polygone

Creates a polygon layer whose features boundaries are generated from a closed line layer features.

../../../../_images/polygonize.png

The yellow polygons generated from the closed lines

Note

La couche de lignes doit avoir des formes fermées afin d’être transformées en polygones.

Paramètres

Input layer [vector: line]
Input line vector layer.
Keep table structure of line layer [boolean]

Optionnel

Check to copy the original attribute of the line layer.

Par défaut : Faux

Sorties

Polygons from lines [vector: polygon]
Vector layer with polygonized features.

Polygons to lines

Takes a polygon layer and creates a line layer, with lines representing the boundaries of the polygons in the input layer.

../../../../_images/polygon_to_lines.png

Black lines as the result of the algorithm

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Input layer [vector: polygon]
Input polygon vector layer.

Sorties

Lines [vector: line]
Lignes depuis la couche de polygones.

Project points (Cartesian)

Projects point geometries by a specified distance and bearing (azimuth), creating a new point layer with the projected points.

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Paramètres

Input layer [vector: point]
Couche vectorielle de points à projeter.
Bearing (degrees from North) [number dataDefined]

Clockwise angle starting from North, in degree (°) unit.

Default: 0.0

Distance [nombre dataDefined]

Distance de décalage pour les géométries, exprimées en unités de la couche en entrée.

Default: 1.0

Sorties

« Projetée » [vecteur: point]
Projected layer at given degrees and distance.

Promote to multipart

Takes a vector layer with singlepart geometries and generates a new one in which all geometries are multipart.

Input features which are already multipart features will remain unchanged.

This algorithm can be used to force geometries to multipart types in order to be compatible with data providers that require multipart features.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.

Sorties

Multiparts [vector: any]
Multiparts vector layer.

Rectangles, ovals, diamonds (fixed)

Creates a buffer area for all the features in an input layer with different shape choice.

Parameters can vary depending on the shape chosen.

../../../../_images/rectangles_ovals_diamond.png

Different buffer shapes

Paramètres

Input layer [vector: point]
Input point vector layer.
Buffer shape [enumeration]

Different shapes available:

  • 0 — Rectangles
  • 1 — Ovals
  • 2 — Diamonds

Par défaut : 0

Width [number]

Width of the buffer shape.

Default: 1.0

Height [number]

Height of the buffer shape.

Default: 1.0

Rotation [number]

Optionnel

Rotation of the buffer shape.

Default: 0.0

Number of segment [number]

How many segment should have the buffer shape.

Default: 36

Sorties

Output [vector: polygon]
Buffer shape in output.

Rectangles, ovals, diamonds (variable)

Creates a buffer area for all the features in an input layer with different shape choice.

Buffer shape parameters are specified through attribute of the input layer.

../../../../_images/rectangles_ovals_diamond_variable.png

Different buffer shapes with different parameters

Paramètres

Input layer [vector: point]
Input point vector layer.
Buffer shape [enumeration]

Different shape available:

  • 0 — Rectangles
  • 1 — Ovals
  • 2 — Diamonds

Par défaut : 0

Width [tablefield: numeric]

Width of the buffer shape.

Default: 1.0

Height [tablefield: numeric]

Height of the buffer shape.

Default: 1.0

Rotation [tablefield: numeric]

Optionnel

Rotation of the buffer shape.

Default: 0.0

Number of segment [number]

How many segment should have the buffer shape.

Default: 36

Sorties

Output [vector: polygon]
Buffer shape in output.

Remove duplicate vertices

Removes duplicate vertices from features, wherever removing the vertices does not result in a degenerate geometry.

The tolerance parameter specifies the tolerance for coordinates when determining whether vertices are identical.

By default, Z values are not considered when detecting duplicate vertices. E.g. two vertices with the same X and Y coordinate but different Z values will still be considered duplicate and one will be removed. If the Use Z Value parameter is true, then the Z values are also tested and vertices with the same X and Y but different Z will be maintained.

Note

Duplicate vertices are not tested between different parts of a multipart geometry, e.g. a multipoint geometry with overlapping points will not be changed by this method.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer with duplicate vertices.
Tolerance [number dataDefined]

Vertices closer than the specified distance are considered duplicates.

Default:0.000001

Use Z value [boolean dataDefined]

Allows to consider the Z coordinate when detecting duplicate vertices ie two points at the same X,Y coordinate but with different Z value are not set as duplicates.

Par défaut : Faux

Sorties

Cleaned [vector: any]
Vector layer without duplicate vertices.

Remove null geometries

Removes any features which do not have a geometry from a vector layer.

All other features will be copied unchanged.

The features with null geometries can be saved to a separate layer.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer with NULL geometries.

Sorties

Non null geometries [vector: any]
Vector layer without NULL geometries.
Null geometries [vector: any]
Vector layer with only NULL geometries.

Reverse line direction

Inverts the direction of a line layer.

../../../../_images/reverse_line.png

Before and after the direction inversion

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Paramètres

Input layer [vector: line]
Input line vector layer to invert the direction.

Sorties

Reversed [vector: line]
Inverted line vector layer.

Rotate

Rotates feature geometries by the specified angle clockwise. The rotation occurs around each feature’s centroid, or optionally around a unique preset point.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Rotation (degrees clockwise) [number dataDefined]

Angle of the rotation in degrees.

Default: 0.0

Rotation anchor point (x, y) [point]

Optionnel

X,Y coordinates of the point to rotate the features around. If not set the rotation occurs around each feature’s centroid.

Sorties

Rotated [vector: any]
Vector layer with rotated geometries.

Segmentize by maximum angle

Segmentizes a geometry by converting curved sections to linear sections.

The segmentization is performed by specifying the maximum allowed radius angle between vertices on the straightened geometry (e.g the angle of the arc created from the original arc center to consecutive output vertices on the linearized geometry). Non-curved geometries will be retained without change.

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Couche vectorielle en entrée.
Maximum angle between vertices (degrees) [number dataDefined]

Maximum allowed radius angle between vertices on the straightened geometry.

Default: 5.0

Sorties

Segmentized [vector: line, polygon]
Vector layer with segmentized geometries.

Segmentize by maximum distance

Segmentizes a geometry by converting curved sections to linear sections.

The segmentization is performed by specifying the maximum allowed offset distance between the original curve and the segmentized representation. Non-curved geometries will be retained without change.

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Couche vectorielle en entrée.
Maximum offset distance [number dataDefined]

Maximum allowed offset distance between the original curve and the segmentized representation, in the layer units.

Default: 1.0

Sorties

Segmentized [vector: line, polygon]
Vector layer with segmentized geometries.

Set M value

Sets the M value for geometries in a layer.

If M values already exist in the layer, they will be overwritten with the new value. If no M values exist, the geometry will be upgraded to include M values and the specified value used as the initial M value for all geometries.

Astuce

Use the identifyIdentify Features button to check the added M value: the results are available in the Identify Results dialog.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
M Value [number dataDefined]

New M value to assign to the features.

Default: 0.0

Sorties

M Added [vector: any]
Vector layer in output with M value.

Set M value from raster

Uses values sampled from a band within a raster layer to set the M value for every overlapping vertex in the feature geometry. The raster values can optionally be scaled by a preset amount.

If M values already exist in the layer, they will be overwritten with the new value. If no M values exist, the geometry will be upgraded to include M values.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer to set the M values to.
Raster layer [raster]
Raster layer to take the M values from.
Band number [raster band]
The raster band to take the M values from if the raster is multiband.
Value for nodata or non-intersecting vertices [number dataDefined]

Value to use in case the vertex does not intersect (a valid pixel of) the raster.

Default: 0.0

Scale factor [number dataDefined]

Scaling value: the band values are multiplied by this value.

Default: 1.0

Sorties

Updated [vector: any]
A vector layer with M values extracted from the provided raster layer.

Set Z value

Sets the Z value for geometries in a layer.

If Z values already exist in the layer, they will be overwritten with the new value. If no Z values exist, the geometry will be upgraded to include Z values and the specified value used as the initial Z value for all geometries.

Astuce

Use the identifyIdentify Features button to check the added Z value: the results are available in the Identify Results dialog.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Z Value [number dataDefined]

New Z value to assign to the features.

Default: 0.0

Sorties

Z Added [vector: any]
Vector layer in output with Z value.

Simplify

Simplifies the geometries in a line or polygon layer. It creates a new layer with the same features as the ones in the input layer, but with geometries containing a lower number of vertices.

The algorithm gives a choice of simplification methods, including distance based (the « Douglas-Peucker » algorithm), area based (« Visvalingam » algorithm) and snapping geometries to grid.

../../../../_images/simplify_geometries.png

Clockwise from top left: source layer and increasing simplification tolerances

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Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Polygon or line vector to simplify.
Simplification method [enumeration]

Method of the simplification.

Options :

  • 0 — Distance (Douglas-Peucker)
  • 1 — Snap to grid
  • 2 — Area (Visvalingam)

Par défaut : 0

Tolerance [number dataDefined]

Threshold tolerance (in units of the layer): if the distance between two nodes is smaller than the tolerance value, the segment will be simplified and vertices will be removed.

Default: 1.0

Sorties

Simplified [vector: line, polygon]
Simplified vector layers in output.

Single sided buffer

Computes a buffer on lines by a specified distance on one side of the line only.

Buffer always results in a polygon layer.

../../../../_images/single_side_buffer.png

Left versus right side buffer on the same vector line layer

Paramètres

Input layer [vector: line]
Input line vector layer.
Distance [number]

Distance radius of the buffer.

Défaut: 10.0

Side [enumeration]

Choose which side the buffer should be created:

  • 0 – Left
  • 1 – Right

Par défaut : 0

Segments [nombre]

Indique le nombre de segments de ligne à utiliser pour approcher un quart de cercle lors de la création de tampons arrondis

Default: 8

Style de jointure [énumération]

Indique si les joints ronds, à angles droits ou biseautés doivent être utilisés lors du décalage des coins dans une ligne. Les options sont :

  • 0 — Rond
  • 1 — Angle droit
  • 2 — Oblique

Par défaut : 0

Limite d'angle droit [nombre]

Only applicable for mitered join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.

Par défaut : 2.0

Sorties

« Tampon » [vecteur : polygone]
One side buffer polygon vector layer.

Smooth

Smooths the geometries in a line or polygon layer. It creates a new layer with the same features as the ones in the input layer, but with geometries containing a higher number of vertices and corners in the geometries smoothed out.

The iterations parameter dictates how many smoothing iterations will be applied to each geometry. A higher number of iterations results in smoother geometries with the cost of greater number of nodes in the geometries.

The offset parameter controls how « tightly » the smoothed geometries follow the original geometries. Smaller values results in a tighter fit, and larger values will create a looser fit.

The maximum angle parameter can be used to prevent smoothing of nodes with large angles. Any node where the angle of the segments to either side is larger than this will not be smoothed. For example, setting the maximum angle to 90 degrees or lower would preserve right angles in the geometry.

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Paramètres

Couche en entrée [vecteur: ligne, polygone ]
Polygon or line vector to smooth.
Iterations [number dataDefined]

With many iterations the resulting layer will have many nodes.

Default: 1

../../../../_images/smooth_geometry_1.png

Different number of iterations cause smoother geometries

Offset [number dataDefined]

Larger values will move the resulting layer borders from the input layer ones.

Default: 0.25

../../../../_images/smooth_geometry_2.png

In blue the input layer. Offset value of 0.25 results in the red line while offset value of 0.50 results in the green line

Maximum node angle to smooth [number dataDefined]

Every node below this value will be smoothed.

Default: 180.0

Sorties

Smoothed [vector: line, polygon]
The smoothed vector layer.

Snap geometries to layer

Snaps the geometries in a layer either to the geometries from another layer, or to geometries within the same layer.

Matching is done based on a tolerance distance, and vertices will be inserted or removed as required to make the geometries match the reference geometries.

Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Vector layer to align.
Reference layer [vector: any]
Vector layer to snap to.
Tolerance [number]

Control how close input vertices need to be to the reference layer geometries before they are snapped. This distance is specified in layer units.

Défaut: 10.0

Behavior [enumeration]

Snapping can be done on an existing node or a segment (its closest point to the vertex to move). Choose between different snapping options:

  • 0 — Prefer aligning nodes, insert extra vertices where required
  • 1 — Prefer closest point, insert extra vertices where required
  • 2 — Prefer aligning nodes, don’t insert new vertices
  • 3 — Prefer closest point, don’t insert new vertices
  • 4 — Move end points only, prefer aligning nodes
  • 5 — Move end points only, prefer closest point
  • 6 — Snap end points to end points only
  • 7 — Snap to anchor nodes (single layer only)

Default: Prefer aligning nodes, insert extra vertices where required

Sorties

Snapped geometry [vector: any]
Vector layer with snapped geometries.

Snap points to grid

Modifies the coordinates of geometries in a vector layer, so that all points or vertices are snapped to the closest point of a grid.

If the snapped geometry cannot be calculated (or is totally collapsed) the feature’s geometry will be cleared.

Snapping can be performed on the X, Y, Z or M axis. A grid spacing of 0 for any axis will disable snapping for that axis.

Note

Snapping to grid may generate an invalid geometry in some corner cases.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer to snap.
X Grid Spacing [number dataDefined]

Spacing of the grid on the X axis.

Default: 1.0

Y Grid Spacing [number dataDefined]

Spacing of the grid on the Y axis.

Default: 1.0

Z Grid Spacing [number dataDefined]

Spacing of the grid on the Z axis.

Default: 0.0

M Grid Spacing [number dataDefined]

Spacing of the grid on the M axis.

Default: 0.0

Sorties

Snapped [vector: any]
Vector layer with snapped geometries.

Subdivide

Subdivides the geometry. The returned geometry will be a collection containing subdivided parts from the original geometry, where no part has more than the specified maximum number of nodes.

This is useful for dividing a complex geometry into less complex parts, easier to spatially index and faster to perform spatial operations. Curved geometries will be segmentized before subdivision.

../../../../_images/subdivide.png

Left the input layer, middle maximum nodes value is 100 and right maximum value is 200

Note

Subdividing a geometry can generate geometry parts that may not be valid and may contain self-intersections.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Vector layer that will have its feature geometries subdivided.
Maximum nodes in parts [number dataDefined]

Maximum number of vertices each new geometry part is allowed to have. Fewer sub-parts for higher values.

Default: 256

Sorties

Subdivided [vector: any]
Output vector layer with subdivided geometries.

Swap X and Y coordinates

Switches the X and Y coordinate values in input geometries.

It can be used to repair geometries which have accidentally had their latitude and longitude values reversed.

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Input vector layer to swap.

Sorties

Swapped [vector: any]
Output swapped vector layer.

Tapered buffers

Creates tapered buffer along line geometries, using a specified start and end buffer diameter.

../../../../_images/tapered_buffer.png

Tapered buffer example

Paramètres

Input layer [vector: line]
Input line vector layer.
Start width [number dataDefined]

Represents the radius of the buffer applied at the start point of the line feature.

Default: 0.0

End width [number dataDefined]

Represents the radius of the buffer applied at the end point of the line feature.

Default: 1.0

Segments [number dataDefined]

Number of the buffer segments.

Default: 16

Sorties

Buffered [vector: polygon]
Variable buffer polygon layer.

Tessellate

Tessellates a polygon geometry layer, dividing the geometries into triangular components.

The output layer consists of multipolygon geometries for each input feature, with each multipolygon consisting of multiple triangle component polygons.

../../../../_images/tessellated.png

Tessellated polygon (right)

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Paramètres

Input layer [vector: polygon]
Polygon vector layer in input.

Sorties

Tesselated [vector: polygon]
Output a multipolygonZ layer with tessellated features.

Transect

Creates transects on vertices for (multi)linestring.

A transect is a line oriented from an angle (by default perpendicular) to the input polylines (at vertices).

Field(s) from feature(s) are returned in the transect with these new fields:

  • TR_FID: ID of the original feature
  • TR_ID: ID of the transect. Each transect have an unique ID
  • TR_SEGMENT: ID of the segment of the linestring
  • TR_ANGLE: Angle in degrees from the original line at the vertex
  • TR_LENGTH: Total length of the transect returned
  • TR_ORIENT: Side of the transect (only on the left or right of the line, or both side)
../../../../_images/transect.png

Dashed red lines represent the transect of the input line layer

Paramètres

Input layer [vector: line]
Input line vector layer.
Length of the transect [number dataDefined]

Length in map unit of the transect.

Default: 5.0

Angle in degrees from the original line at the vertices [number dataDefined]

Change the angle of the transect.

Default: 90.0

Side to create the transect [enumeration]

Choose the side of the transect. Available options are:

  • 0 — Left
  • 1 — Right
  • 2 — Both

Par défaut : 0

Sorties

Transect [vector: line]
Transect of the source line vector layer.

Translate

Moves the geometries within a layer, by offsetting with a predefined X and Y displacement.

Z and M values present in the geometry can also be translated.

../../../../_images/translate_geometry.png

Dashed lines represent the translated geometry of the input layer

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Paramètres

Couche en entrée [ vecteur : n’importe lequel]
Couche vectorielle en entrée.
Offset distance (x-axis) [number dataDefined]

Displacement to apply on the X axis.

Default: 0.0

Offset distance (y-axis) [number dataDefined]

Displacement to apply on the Y axis.

Default: 0.0

Offset distance (z-axis) [number dataDefined]

Displacement to apply on the Z axis.

Default: 0.0

Offset distance (m values) [number dataDefined]

Offset value to apply on M.

Default: 0.0

Sorties

Translated [vector: any]
Translated (moved) vector layer.

Variable distance buffer (Processing Modeler only)

Computes a buffer area for all the features in an input layer.

The size of the buffer for a given feature is defined by an attribute, so it allows different features to have different buffer sizes.

Paramètres

Label Name Type Description
Input layer INPUT [vector: any] Input vector layer
Distance field DISTANCE [tablefield: numeric] Attribute for the distance radius of the buffer
Segments SEGMENTS

[number]

Défaut: 5

Indique le nombre de segments de ligne à utiliser pour approcher un quart de cercle lors de la création de tampons arrondis
Dissolve result DISSOLVE

[boolean]

Par défaut : Faux

Choose to dissolve the final buffer, resulting in a single feature covering all input features.

../../../../_images/buffer_dissolve1.png

Normal and dissolved buffer

End cap style END_CAP_STYLE [enumeration]

Controls how line endings are handled in the buffer.

../../../../_images/buffer_cap_style.png

Style de terminaison rond, plat et carré

Join style JOIN_STYLE [enumeration] Specifies whether round, miter or beveled joins should be used when offsetting corners in a line.
Miter limit MITER_LIMIT

[number]

Default: 2.0

Only applicable for mitered join styles, and controls the maximum distance from the offset curve to use when creating a mitered join.

Sorties

Label Name Type Description
Buffer OUTPUT [vector: polygon] Couche vectorielle de polygone correspondant au tampon.

Voir également

Tampon

Variable width buffer (by M value)

Creates variable width buffers along lines, using the M value of the line geometries as the diameter of the buffer at each vertex.

../../../../_images/variable_buffer_m.png

Variable buffer example

Paramètres

Input layer [vector: line]
Line vector layer in input.
Segments [number dataDefined]

Number of the buffer segments. It can be a unique value (same value for all the features) or it can be taken from features data (different value depending on the feature attribute).

Default: 16

Sorties

Buffered [vector: polygon]
Variable buffer polygon layer.

Voronoi polygons

Takes a points layer and generates a polygon layer containing the Voronoi polygons (known also as Thiessen polygons) corresponding to those input points.

Any location within a Voronoi polygon is closer to the associated point than to any other point.

../../../../_images/voronoi1.png

Voronoi polygons

Menu par défaut: Vecteur ‣ Outils de géométrie

Paramètres

Input layer [vector: point]
Input point vector layer.
Buffer region [number]

Area of the Voronoi polygons or of the input layer.

Default: 0.0

Sorties

Voronoi polygons [vector: polygon]
Voronoi polygons of the input point vector layer.