27.1.9. Network analysis

27.1.9.1. Service area (from layer)

Returns all the edges or parts of edges of a network that can be reached within a distance or a time, starting from a point layer. This allows evaluation of accessibility within a network, e.g. what are the places I can navigate to on a road network without spending cost greater than a given value (the cost can be distance or time).

参数

Basic parameters

标注	名称	类型	描述
Vector layer representing network	INPUT	[vector: line]	Line vector layer representing the network to be covered
Vector layer with start points	START_POINTS	[vector: point]	Point vector layer whose features are used as start points to generate the service areas
Path type to calculate	STRATEGY	[enumeration] Default: 0	The type of path to calculate. One of: 0 --- Shortest 1 --- Fastest
Travel cost (distance for "Shortest", time for "Fastest")	TRAVEL_COST	[数字] Default: 0	The value is estimated as a distance (in the network layer units) when looking for the Shortest path and as time (in hours) for the Fastest path.
Service area (lines)	OUTPUT_LINES	[vector: line] Default: [Create temporary layer]	Specify the output line layer for the service area. One of: Skip Output Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。
Service area (boundary nodes)	OUTPUT	[vector: point] Default: [Skip output]	Specify the output point layer for the service area boundary nodes. One of: Skip Output Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

Advanced parameters

标注	名称	类型	描述
Direction field 可选	DIRECTION_FIELD	[tablefield: string] Default: 0.0	The field used to specify directions for the network edges. The values used in this field are specified with the three parameters Value for forward direction, Value for backward direction and Value for both directions. Forward and reverse directions correspond to a one-way edge, "both directions" indicates a two-way edge. If a feature does not have a value in this field, or no field is set then the default direction setting (provided with the Default direction parameter) is used.
Value for forward direction 可选	VALUE_FORWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a forward direction
Value for backward direction 可选	VALUE_BACKWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a backward direction
Value for both directions 可选	VALUE_BOTH	[string] Default: '' (empty string)	Value set in the direction field to identify bidirectional edges
Default direction	DEFAULT_DIRECTION	[enumeration] Default: 2	If a feature has no value set in the direction field or if no direction field is set, then this direction value is used. One of: 0 --- Forward direction 1 --- Backward direction 2 --- Both directions
Speed field 可选	SPEED_FIELD	[tablefield: string]	Field providing the speed value (in km/h) for the edges of the network when looking for the fastest path. If a feature does not have a value in this field, or no field is set then the default speed value (provided with the Default speed parameter) is used.
Default speed (km/h)	DEFAULT_SPEED	[数字] Default: 50.0	Value to use to calculate the travel time if no speed field is provided for an edge
Topology tolerance	TOLERANCE	[数字] Default: 0.0	Two lines with nodes closer than the specified tolerance are considered connected

Include upper/lower bound points

INCLUDE_BOUNDS

[boolean] Default: False

Creates a point layer output with two points for each edge at the boundaries of the service area. One point is the start of that edge, the other is the end.

输出

标注	名称	类型	描述
Service area (boundary nodes)	OUTPUT	[vector: point]	The output point layer with the service area boundary nodes.
Service area (lines)	OUTPUT_LINES	[vector: line]	Line layer representing the parts of the network that can be serviced by the start points, for the given cost.

Python代码

Algorithm ID: qgis:serviceareafromlayer

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.9.2. Service area (from point)

Returns all the edges or parts of edges of a network that can be reached within a given distance or time, starting from a point feature. This allows the evaluation of accessibility within a network, e.g. what are the places I can navigate to on a road network without spending a cost greater than a given value (the cost can be distance or time).

参数

Basic parameters

标注	名称	类型	描述
Vector layer representing the network	INPUT	[vector: line]	Line vector layer representing the network to be covered
Start point (x, y)	START_POINT	[coordinates]	Coordinate of the point to calculate the service area around.
Path type to calculate	STRATEGY	[enumeration] Default: 0	The type of path to calculate. One of: 0 --- Shortest 1 --- Fastest
Travel cost (distance for "Shortest", time for "Fastest")	TRAVEL_COST	[数字] Default: 0	The value is estimated as a distance (in the network layer units) when looking for the Shortest path and as time (in hours) for the Fastest path.
Service area (lines)	OUTPUT_LINES	[vector: line] Default: [Create temporary layer]	Specify the output line layer for the service area. One of: Skip Output Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。
Service area (boundary nodes)	OUTPUT	[vector: point] Default: [Skip output]	Specify the output point layer for the service area boundary nodes. One of: Skip Output Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

Advanced parameters

标注	名称	类型	描述
Direction field 可选	DIRECTION_FIELD	[tablefield: string] Default: 0.0	The field used to specify directions for the network edges. The values used in this field are specified with the three parameters Value for forward direction, Value for backward direction and Value for both directions. Forward and reverse directions correspond to a one-way edge, "both directions" indicates a two-way edge. If a feature does not have a value in this field, or no field is set then the default direction setting (provided with the Default direction parameter) is used.
Value for forward direction 可选	VALUE_FORWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a forward direction
Value for backward direction 可选	VALUE_BACKWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a backward direction
Value for both directions 可选	VALUE_BOTH	[string] Default: '' (empty string)	Value set in the direction field to identify bidirectional edges
Default direction	DEFAULT_DIRECTION	[enumeration] Default: 2	If a feature has no value set in the direction field or if no direction field is set, then this direction value is used. One of: 0 --- Forward direction 1 --- Backward direction 2 --- Both directions
Speed field 可选	SPEED_FIELD	[tablefield: string]	Field providing the speed value (in km/h) for the edges of the network when looking for the fastest path. If a feature does not have a value in this field, or no field is set then the default speed value (provided with the Default speed parameter) is used.
Default speed (km/h)	DEFAULT_SPEED	[数字] Default: 50.0	Value to use to calculate the travel time if no speed field is provided for an edge
Topology tolerance	TOLERANCE	[数字] Default: 0.0	Two lines with nodes closer than the specified tolerance are considered connected

Include upper/lower bound points

INCLUDE_BOUNDS

[boolean] Default: False

Creates a point layer output with two points for each edge at the boundaries of the service area. One point is the start of that edge, the other is the end.

输出

标注	名称	类型	描述
Service area (boundary nodes)	OUTPUT	[vector: point]	The output point layer with the service area boundary nodes.
Service area (lines)	OUTPUT_LINES	[vector: line]	Line layer representing the parts of the network that can be serviced by the start point, for the given cost.

Python代码

Algorithm ID: native:serviceareafrompoint

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.9.3. Shortest path (layer to point)

Computes the optimal (shortest or fastest) routes from multiple start points defined by a vector layer and a given end point.

参数

Basic parameters

标注	名称	类型	描述
Vector layer representing network	INPUT	[vector: line]	Line vector layer representing the network to be covered
Path type to calculate	STRATEGY	[enumeration] Default: 0	The type of path to calculate. One of: 0 --- Shortest 1 --- Fastest
Vector layer with start points	START_POINTS	[vector: point]	Point vector layer whose features are used as start points of the routes
End point (x, y)	END_POINT	[coordinates]	Point feature representing the end point of the routes
Shortest path	OUTPUT	[vector: line]	Specify the output line layer for the shortest paths. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

Advanced parameters

标注	名称	类型	描述
Direction field 可选	DIRECTION_FIELD	[tablefield: string] Default: 0.0	The field used to specify directions for the network edges. The values used in this field are specified with the three parameters Value for forward direction, Value for backward direction and Value for both directions. Forward and reverse directions correspond to a one-way edge, "both directions" indicates a two-way edge. If a feature does not have a value in this field, or no field is set then the default direction setting (provided with the Default direction parameter) is used.
Value for forward direction 可选	VALUE_FORWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a forward direction
Value for backward direction 可选	VALUE_BACKWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a backward direction
Value for both directions 可选	VALUE_BOTH	[string] Default: '' (empty string)	Value set in the direction field to identify bidirectional edges
Default direction	DEFAULT_DIRECTION	[enumeration] Default: 2	If a feature has no value set in the direction field or if no direction field is set, then this direction value is used. One of: 0 --- Forward direction 1 --- Backward direction 2 --- Both directions
Speed field 可选	SPEED_FIELD	[tablefield: string]	Field providing the speed value (in km/h) for the edges of the network when looking for the fastest path. If a feature does not have a value in this field, or no field is set then the default speed value (provided with the Default speed parameter) is used.
Default speed (km/h)	DEFAULT_SPEED	[数字] Default: 50.0	Value to use to calculate the travel time if no speed field is provided for an edge
Topology tolerance	TOLERANCE	[数字] Default: 0.0	Two lines with nodes closer than the specified tolerance are considered connected

输出

标注	名称	类型	描述
Shortest path	OUTPUT	[vector: line]	Line layer of the shortest or fastest path from each of the start points to the end point

Python代码

Algorithm ID: native:shortestpathlayertopoint

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.9.4. Shortest path (point to layer)

Computes the optimal (shortest or fastest) routes between a given start point and multiple end points defined by a point vector layer.

参数

Basic parameters

标注	名称	类型	描述
Vector layer representing network	INPUT	[vector: line]	Line vector layer representing the network to be covered
Path type to calculate	STRATEGY	[enumeration] Default: 0	The type of path to calculate. One of: 0 --- Shortest 1 --- Fastest
Start point (x, y)	START_POINT	[coordinates]	Point feature representing the start point of the routes
Vector layer with end points	END_POINTS	[vector: point]	Point vector layer whose features are used as end points of the routes
Shortest path	OUTPUT	[vector: line]	Specify the output line layer for the shortest paths. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

Advanced parameters

标注	名称	类型	描述
Direction field 可选	DIRECTION_FIELD	[tablefield: string] Default: 0.0	The field used to specify directions for the network edges. The values used in this field are specified with the three parameters Value for forward direction, Value for backward direction and Value for both directions. Forward and reverse directions correspond to a one-way edge, "both directions" indicates a two-way edge. If a feature does not have a value in this field, or no field is set then the default direction setting (provided with the Default direction parameter) is used.
Value for forward direction 可选	VALUE_FORWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a forward direction
Value for backward direction 可选	VALUE_BACKWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a backward direction
Value for both directions 可选	VALUE_BOTH	[string] Default: '' (empty string)	Value set in the direction field to identify bidirectional edges
Default direction	DEFAULT_DIRECTION	[enumeration] Default: 2	If a feature has no value set in the direction field or if no direction field is set, then this direction value is used. One of: 0 --- Forward direction 1 --- Backward direction 2 --- Both directions
Speed field 可选	SPEED_FIELD	[tablefield: string]	Field providing the speed value (in km/h) for the edges of the network when looking for the fastest path. If a feature does not have a value in this field, or no field is set then the default speed value (provided with the Default speed parameter) is used.
Default speed (km/h)	DEFAULT_SPEED	[数字] Default: 50.0	Value to use to calculate the travel time if no speed field is provided for an edge
Topology tolerance	TOLERANCE	[数字] Default: 0.0	Two lines with nodes closer than the specified tolerance are considered connected

输出

标注	名称	类型	描述
Shortest path	OUTPUT	[vector: line]	Line layer of the shortest or fastest path from each of the start points to the end point

Python代码

Algorithm ID: native:shortestpathpointtolayer

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。

27.1.9.5. Shortest path (point to point)

Computes the optimal (shortest or fastest) route between a given start point and a given end point.

参数

Basic parameters

标注	名称	类型	描述
Vector layer representing network	INPUT	[vector: line]	Line vector layer representing the network to be covered
Path type to calculate	STRATEGY	[enumeration] Default: 0	The type of path to calculate. One of: 0 --- Shortest 1 --- Fastest
Start point (x, y)	START_POINT	[coordinates]	Point feature representing the start point of the routes
End point (x, y)	END_POINT	[coordinates]	Point feature representing the end point of the routes
Shortest path	OUTPUT	[vector: line]	Specify the output line layer for the shortest paths. One of: Create Temporary Layer (TEMPORARY_OUTPUT) 保存到文件… Save to Geopackage… Save to Database Table… 文件编码也可以在此更改。

Advanced parameters

标注	名称	类型	描述
Direction field 可选	DIRECTION_FIELD	[tablefield: string] Default: 0.0	The field used to specify directions for the network edges. The values used in this field are specified with the three parameters Value for forward direction, Value for backward direction and Value for both directions. Forward and reverse directions correspond to a one-way edge, "both directions" indicates a two-way edge. If a feature does not have a value in this field, or no field is set then the default direction setting (provided with the Default direction parameter) is used.
Value for forward direction 可选	VALUE_FORWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a forward direction
Value for backward direction 可选	VALUE_BACKWARD	[string] Default: '' (empty string)	Value set in the direction field to identify edges with a backward direction
Value for both directions 可选	VALUE_BOTH	[string] Default: '' (empty string)	Value set in the direction field to identify bidirectional edges
Default direction	DEFAULT_DIRECTION	[enumeration] Default: 2	If a feature has no value set in the direction field or if no direction field is set, then this direction value is used. One of: 0 --- Forward direction 1 --- Backward direction 2 --- Both directions
Speed field 可选	SPEED_FIELD	[tablefield: string]	Field providing the speed value (in km/h) for the edges of the network when looking for the fastest path. If a feature does not have a value in this field, or no field is set then the default speed value (provided with the Default speed parameter) is used.
Default speed (km/h)	DEFAULT_SPEED	[数字] Default: 50.0	Value to use to calculate the travel time if no speed field is provided for an edge
Topology tolerance	TOLERANCE	[数字] Default: 0.0	Two lines with nodes closer than the specified tolerance are considered connected

输出

标注	名称	类型	描述
Shortest path	OUTPUT	[vector: line]	Line layer of the shortest or fastest path from each of the start point to the end point

Python代码

Algorithm ID: native:shortestpathpointtopoint

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

当你在数据处理工具箱某个算法前悬停时，算法 id 将会展现。*参数字*将会提供参数的名称与数值。参考详见`数据处理_控制台`以获取如何从Python控制台中运行数据处理算法。