24.1.18. Vector selection

Extract by attribute
Extract by expression
Extract by location
Random extract
Random extract within subsets
Seleção aleatória
Random selection within subsets
Select by attribute
Select by expression
Selecionar pela localização

24.1.18.1. Extract by attribute 

Creates two vector layers from an input layer: one will contain only matching features while the second will contain all the non-matching features.

The criteria for adding features to the resulting layer is based on the values of an attribute from the input layer.

Ver também

Select by attribute

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[vector: any]	Layer to extract features from.
Selection attribute	`CAMPO`	[tablefield: any]	Filtering field of the layer
Operator	`OPERATOR`	[enumeration] Padrão: 0	Many different operators are available: 0 — = 1 — ≠ 2 — > 3 — >= 4 — < 5 — <= 6 — begins with 7 — contains 8 — is null 9 — is not null 10 — does not contain
Value Opcional	`VALOR`	[string]	Value to be evaluated
Extracted (attribute)	`SAÍDA`	[same as input] Default: `[Create Temporary Layer]`	Specify the output vector layer for matching features. One of: Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS… A codificação do arquivo também pode ser alterada aqui.
Extracted (non-matching)	`FAIL_OUTPUT`	[same as input] Default: `[Skip output]`	Specify the output vector layer for non-matching features. One of: Ignorar Saída Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS…

Saídas

Etiqueta	Nome	Tipo	Descrição
Extracted (attribute)	`SAÍDA`	[same as input]	Vector layer with matching features from the input layer
Extracted (non-matching)	`FAIL_OUTPUT`	[same as input]	Vector layer with non-matching features from the input layer

Python code

Algorithm ID: qgis:extractbyattribute

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.2. Extract by expression 

Creates two vector layers from an input layer: one will contain only matching features while the second will contain all the non-matching features.

The criteria for adding features to the resulting layer is based on a QGIS expression. For more information about expressions see the Expressões.

Ver também

Select by expression

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[vector: any]	Camada vetorial de entrada
Expressão	`EXPRESSÃO`	[expression]	Expression to filter the vector layer
Matching features	`SAÍDA`	[same as input] Default: `[Create Temporary Layer]`	Specify the output vector layer for matching features. One of: Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS… A codificação do arquivo também pode ser alterada aqui.
Non-matching	`FAIL_OUTPUT`	[same as input] Default: `[Skip output]`	Specify the output vector layer for non-matching features. One of: Ignorar Saída Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS…

Saídas

Etiqueta	Nome	Tipo	Descrição
Matching features	`SAÍDA`	[same as input]	Vector layer with matching features from the input layer
Non-matching	`FAIL_OUTPUT`	[same as input]	Vector layer with non-matching features from the input layer

Python code

Algorithm ID: qgis:extractbyexpression

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.3. Extract by location 

Creates a new vector layer that only contains matching features from an input layer.

The criteria for adding features to the resulting layer is based on the spatial relationship between each feature and the features in an additional layer.

../../../../_images/selectbylocation.png — Fig. 24.100 In this example, the dataset from which we want to select (the *source vector layer*) consists of the green circles, the orange rectangle is the dataset that it is being compared to (the *intersection vector layer*).

Available geometric predicates are:

Intersect: Tests whether a geometry intersects another. Returns 1 (true) if the geometries spatially intersect (share any portion of space - overlap or touch) and 0 if they don’t. In the picture above, this will select circles 1, 2 and 3.
Contain: Retorna 1 (verdadeiro) se e somente se nenhum ponto de b estiver no exterior de a e pelo menos um ponto do interior de b estiver no interior de a. Na imagem, nenhum círculo é selecionado, mas o retângulo seria se você o selecionasse ao contrário, pois ele contém um círculo completamente. Este é o oposto de are within.
Disjoint: Returns 1 (true) if the geometries do not share any portion of space (no overlap, not touching). Only circle 4 is selected.
Igual: Retorna 1 (verdadeiro) se e somente se as geometrias forem exatamente iguais. Nenhum círculo será selecionado.
Touch: Testa se uma geometria toca em outra. Retorna 1 (verdadeiro) se as geometrias tiverem pelo menos um ponto em comum, mas seus interiores não se cruzam. Somente o círculo 3 está selecionado.
Overlap: Testa se uma geometria sobrepõe outra. Retorna 1 (verdadeiro) se as geometrias compartilharem espaço, têm a mesma dimensão, mas não estão completamente contidas uma na outra. Somente o círculo 2 está selecionado.
Are within: Tests whether a geometry is within another. Returns 1 (true) if geometry a is completely inside geometry b. Only circle 1 is selected.
Cross: Retorna 1 (verdadeiro) se as geometrias fornecidas tiverem alguns pontos internos em comum, mas não todos, e o cruzamento real tiver uma dimensão menor que a maior geometria fornecida. Por exemplo, uma linha cruzando um polígono cruzará como uma linha (selecionada). O cruzamento de duas linhas cruzará como um ponto (selecionado). Dois polígonos cruzam como um polígono (não selecionado).

Ver também

Selecionar pela localização

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Extract features from	`ENTRADA`	[vector: any]	Camada vetorial de entrada
Where the features (geometric predicate)	`PREDICATE`	[enumeration] [list] Padrão: [0]	Spatial condition for the selection. One or more of: 0 — intersect 1 — contain 2 — disjoint 3 — equal 4 — touch 5 — overlap 6 — are within 7 — cross If more than one condition is chosen, at least one of them (OR operation) has to be met for a feature to be extracted.
By comparing to the features from	`INTERSECT`	[vector: any]	Intersection vector layer
Extracted (location)	`SAÍDA`	[same as input] Default: `[Create temporary layer]`	Specify the output vector layer for the features that have the chosen spatial relationship(s) with one or more features in the comparison layer. One of: Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS…

Saídas

Etiqueta	Nome	Tipo	Descrição
Extracted (location)	`SAÍDA`	[same as input]	Vector layer with features from the input layer that have the chosen spatial relationship(s) with one or more features in the comparison layer.

Python code

Algorithm ID: qgis:extractbylocation

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.4. Random extract 

Takes a vector layer and generates a new one that contains only a subset of the features in the input layer.

The subset is defined randomly, based on feature IDs, using a percentage or count value to define the total number of features in the subset.

Ver também

Seleção aleatória

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[vector: any]	Source vector layer to select the features from
Método	`MÉTODO`	[enumeration] Padrão: 0	Random selection methods. One of: 0 — Number of selected features 1 — Percentage of selected features
Number/percentage of selected features	`NÚMERO`	[number] Padrão: 10	Number or percentage of features to select
Extracted (random)	`SAÍDA`	[vector: any] Default: `[Create temporary layer]`	Specify the output vector layer for the randomly selected features. One of: Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS… Vector layer containing randomly selected features

Saídas

Etiqueta	Nome	Tipo	Descrição
Extracted (random)	`SAÍDA`	[same as input]	Vector layer containing randomly selected features from the input layer

Python code

Algorithm ID: qgis:randomextract

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.5. Random extract within subsets 

Takes a vector layer and generates a new one that contains only a subset of the features in the input layer.

The subset is defined randomly, based on feature IDs, using a percentage or count value to define the total number of features in the subset. The percentage/count value is not applied to the whole layer, but instead to each category. Categories are defined according to a given attribute.

Ver também

Random selection within subsets

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[vector: any]	Vector layer to select the features from
ID field	`CAMPO`	[tablefield: any]	Category of the source vector layer to select the features from
Método	`MÉTODO`	[enumeration] Padrão: 0	Random selection method. One of: 0 — Number of selected features 1 — Percentage of selected features
Number/percentage of selected features	`NÚMERO`	[number] Padrão: 10	Number or percentage of features to select
Extracted (random stratified)	`SAÍDA`	[same as input] Default: `[Create temporary layer]`	Specify the output vector layer for the randomly selected features. One of: Create Temporary Layer (`TEMPORARY_OUTPUT`) Salvar para Arquivo… Salvar para Geopackage… Salvar para Tabela PostGIS… A codificação do arquivo também pode ser alterada aqui.

Saídas

Etiqueta	Nome	Tipo	Descrição
Extracted (random stratified)	`SAÍDA`	[same as input]	Vector layer containing randomly selected features from the input layer

Python code

Algorithm ID: qgis:randomextractwithinsubsets

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.6. Seleção aleatória 

Takes a vector layer and selects a subset of its features. No new layer is generated by this algorithm.

The subset is defined randomly, based on feature IDs, using a percentage or count value to define the total number of features in the subset.

Default menu: Vector ► Research Tools

Ver também

Random extract

Parâmetros

Etiqueta

Nome

Tipo

Descrição

Camada de entrada

ENTRADA

[vector: any]

Vector layer for the selection

Método

MÉTODO

[enumeration]

Padrão: 0

Random selection method. One of:

0 — Number of selected features
1 — Percentage of selected features

Number/percentage of selected features

NÚMERO

[number]

Padrão: 10

Number or percentage of features to select

Saídas

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[same as input]	The input layer with features selected

Python code

Algorithm ID: qgis:randomselection

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.7. Random selection within subsets 

Takes a vector layer and selects a subset of its features. No new layer is generated by this algorithm.

The subset is defined randomly, based on feature IDs, using a percentage or count value to define the total number of features in the subset.

The percentage/count value is not applied to the whole layer, but instead to each category.

Categories are defined according to a given attribute, which is also specified as an input parameter for the algorithm.

No new outputs are created.

Default menu: Vector ► Research Tools

Ver também

Random extract within subsets

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[vector: any]	Vector layer to select features in
ID field	`CAMPO`	[tablefield: any]	Category of the input layer to select the features from
Método	`MÉTODO`	[enumeration] Padrão: 0	Random selection method. One of: 0 — Number of selected features 1 — Percentage of selected features
Number/percentage of selected features	`NÚMERO`	[number] Padrão: 10	Number or percentage of features to select

Saídas

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[same as input]	The input layer with features selected

Python code

Algorithm ID: qgis:randomselectionwithinsubsets

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.8. Select by attribute 

Creates a selection in a vector layer.

The criteria for selecting features is based on the values of an attribute from the input layer.

Ver também

Extract by attribute

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[vector: any]	Vector layer to select features in
Selection attribute	`CAMPO`	[tablefield: any]	Filtering field of the layer
Operator	`OPERATOR`	[enumeration] Padrão: 0	Many different operators are available: 0 — = 1 — ≠ 2 — > 3 — >= 4 — < 5 — <= 6 — begins with 7 — contains 8 — is null 9 — is not null 10 — does not contain
Value Opcional	`VALOR`	[string]	Value to be evaluated
Modify current selection by	`MÉTODO`	[enumeration] Padrão: 0	How the selection of the algorithm should be managed. One of: 0 — creating new selection 1 — adding to current selection 2 — removing from current selection 3 — selecting within current selection

Saídas

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[same as input]	The input layer with features selected

Python code

Algorithm ID: qgis:selectbyattribute

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.9. Select by expression 

Creates a selection in a vector layer.

The criteria for selecting features is based on a QGIS expression. For more information about expressions see the Expressões.

Ver também

Extract by expression

Parâmetros

Etiqueta

Nome

Tipo

Descrição

Camada de entrada

ENTRADA

[vector: any]

Camada vetorial de entrada

Expressão

EXPRESSÃO

[expression]

Expression to filter the input layer

Modify current selection by

MÉTODO

[enumeration]

Padrão: 0

How the selection of the algorithm should be managed. One of:

0 — creating new selection
1 — adding to current selection
2 — removing from current selection
3 — selecting within current selection

Saídas

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[same as input]	The input layer with features selected

Python code

Algorithm ID: qgis:selectbyexpression

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.

24.1.18.10. Selecionar pela localização 

Creates a selection in a vector layer.

The criteria for selecting features is based on the spatial relationship between each feature and the features in an additional layer.

Available geometric predicates are:

Intersect: Tests whether a geometry intersects another. Returns 1 (true) if the geometries spatially intersect (share any portion of space - overlap or touch) and 0 if they don’t. In the picture above, this will select circles 1, 2 and 3.
Contain: Retorna 1 (verdadeiro) se e somente se nenhum ponto de b estiver no exterior de a e pelo menos um ponto do interior de b estiver no interior de a. Na imagem, nenhum círculo é selecionado, mas o retângulo seria se você o selecionasse ao contrário, pois ele contém um círculo completamente. Este é o oposto de are within.
Disjoint: Returns 1 (true) if the geometries do not share any portion of space (no overlap, not touching). Only circle 4 is selected.
Igual: Retorna 1 (verdadeiro) se e somente se as geometrias forem exatamente iguais. Nenhum círculo será selecionado.
Touch: Testa se uma geometria toca em outra. Retorna 1 (verdadeiro) se as geometrias tiverem pelo menos um ponto em comum, mas seus interiores não se cruzam. Somente o círculo 3 está selecionado.
Overlap: Testa se uma geometria sobrepõe outra. Retorna 1 (verdadeiro) se as geometrias compartilharem espaço, têm a mesma dimensão, mas não estão completamente contidas uma na outra. Somente o círculo 2 está selecionado.
Are within: Tests whether a geometry is within another. Returns 1 (true) if geometry a is completely inside geometry b. Only circle 1 is selected.
Cross: Retorna 1 (verdadeiro) se as geometrias fornecidas tiverem alguns pontos internos em comum, mas não todos, e o cruzamento real tiver uma dimensão menor que a maior geometria fornecida. Por exemplo, uma linha cruzando um polígono cruzará como uma linha (selecionada). O cruzamento de duas linhas cruzará como um ponto (selecionado). Dois polígonos cruzam como um polígono (não selecionado).

Default menu: Vector ► Research Tools

Ver também

Extract by location

Parâmetros

Etiqueta	Nome	Tipo	Descrição
Select features from	`ENTRADA`	[vector: any]	Camada vetorial de entrada
Where the features (geometric predicate)	`PREDICATE`	[enumeration] [list] Padrão: [0]	Spatial condition for the selection. One or more of: 0 — intersect 1 — contain 2 — disjoint 3 — equal 4 — touch 5 — overlap 6 — are within 7 — cross If more than one condition is chosen, at least one of them (OR operation) has to be met for a feature to be extracted.
By comparing to the features from	`INTERSECT`	[vector: any]	Intersection vector layer
Modify current selection by	`MÉTODO`	[enumeration] Padrão: 0	How the selection of the algorithm should be managed. One of: 0 — creating new selection 1 — adding to current selection 2 — selecting within current selection 3 — removing from current selection

Saídas

Etiqueta	Nome	Tipo	Descrição
Camada de entrada	`ENTRADA`	[same as input]	The input layer with features selected

Python code

Algorithm ID: qgis:selectbylocation

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 Usando os algoritmos do processamento a partir do Terminal Python. for details on how to run processing algorithms from the Python console.