LineCombiner

Categories

Geometries

Related Transformers

Intersector

LineBuilder

LineCloser

LineExtender

PathBuilder

Snapper

Connects line features that meet at common start or end points to create longer lines or paths.

Jump to Configuration

Typical Uses

  • Connecting multiple lines into longer, continuous lines or paths

How does it work?

The LineCombiner receives features with line geometry and merges them where they meet at the same start or end x and y coordinates, producing a continuous line or path, depending on parameter choices and input feature properties.

Attribute values can be optionally used to group the input features to be combined, with various options for attribute accumulation including the creation of List attributes .

Z Values

Z values are supported and optional. The Consider Node Elevation parameter dictates how they are handled:

  • If Yes, nodes will only be combined if the x, y, and z coordinates are an exact match.

  • If No, nodes are combined where the x and y coordinates are a match, and the z values are further handled according to the Connect Z Mode parameter.

Junctions, Intersections, and Crossings

Input line features may cross and intersect in numerous ways, and their handling depends on a combination of parameters.

Crossing

A simple crossing, where no vertices exist at the point of intersection, is handled as if the lines do not interact at all. There are no junctions.

Input

Lines have a Name attribute, either A or B.

They cross but do not intersect.

Output

Two lines are output.

Parameter settings:

Combine on Attributes: None

or

Combine on Attributes: Name

Intersections/Junctions

The LineCombiner cannot connect more than two lines at a single node. Combinations are determined by the Combine On Attributes and Junctions parameters.

Input

Lines have a Name attribute, either A or B.

They intersect, having a node in common where they meet.

This junction has four line segments converging.

Output

Two lines are output, each passing through the junction.

Parameter settings:

Combine on Attributes: Name

Junctions: Consider Attribute Values

Output

Four lines are output, each terminating at the junction.

Parameter settings:

Combine on Attributes: Name

Junctions: Ignore Attribute Values

or

Combine on Attributes: No items selected.

Junctions: Consider Attribute Values

or

Combine on Attributes: No items selected.

Junctions: Ignore Attribute Values

Mid-line Intersections

Where a line meets another at a point along the line (not an end point), the Input Feature Topology parameter determines the output.

Both features must have a vertex in common.

Input

Two lines are input, with the attribute Name either A or B.

They meet as a T intersection, where B touches A mid-line.

Both lines have a vertex at that location.

Output

Two lines are output unchanged.

Parameter settings:

Input Feature Topology: End Noded

Output

Three lines are output. Input line A is split at the junction.

Parameter settings:

Input Feature Topology: Vertex Noded

Output Lines and Paths

Output features are either lines or paths, depending on both parameters and the properties of the input features.

Lines are output unless paths are required. When lines are created, the matching combined nodes are collapsed into a single node (pseudonodes are removed).

Paths retain all input nodes, keeping the input features intact as segments in a longer complex path geometry. Paths are output if Preserve Lines as Path Segments is Yes, or if the input geometry has properties that vary, such as measures, traits or geometry names.

Duplicate input features are discarded.

Note that path geometry is not supported in all output formats. See also: Line and Path geometry.

Examples

In this example, we have a set of streets that have been split at all intersections, producing multiple individual lines for each street. We want to reconstruct the original whole streets.

Note that the features have a NAME attribute, which will be used to combine them.

The features are routed into a LineCombiner.

In the parameter dialog, Combine On Attributes is set to NAME.

The output features are continuous lines. .

Usage Notes

Creating and Modifying Linear Features

These transformers work with lines in a variety of ways.

 

Function

Transformer Description

LineBuilder

Simple creation of lines from lines and/or points.

Connects sequential point and/or line features to create line or area geometry.

LineCombiner

Combining adjoining lines into longer lines or complex paths, with more advanced geometry handling options than the LineBuilder.

Connects line features that meet at common start or end points to create longer lines or paths.

PathBuilder

Combining arcs and lines into longer paths.

Connects sequential line and/or arc features to create path geometry, preserving input segments.

LineCloser

Turning linear features into areas.

Turns input linear features into areas by adding their start point as the end point.

LineExtender

Making linear features longer by a specific amount and at an appropriate angle.

Creates two-point extensions to linear features that extend the feature by a user-specified length.

Chopper

Chopping features into smaller features.

Breaks input features into points, lines, or areas. Chopped features contain the same set of vertices as input features.

PathSplitter

Breaking a path into its component segments (lines and arcs).

Decomposes a path feature into its component segments.

Snipper

Shortening linear features by cutting off the ends.

Shortens the geometry of a line feature from the ends by snipping specified distances, indices, or measure values. It operates on features with simple line geometry and polygons without holes.

LineOnAreaOverlayer

Intersecting lines and areas.

Performs a line-on-area overlay, either splitting lines where they intersect area boundaries or subdividing areas where split by lines. Attributes may be shared between related lines and areas (spatial join).

LineOnLineOverlayer

Intersecting lines and lines.

Performs a line-on-line overlay in which all input lines are intersected against each other and resultant line features are created and output. Intersection points are turned into point features that can contain the merged list of attributes of the original intersected lines.

PointOnLineOverlayer

Finding where points lay on lines.

Performs a point-on-line overlay. Each input line is split at its closest place to any point within the specified point tolerance, and attributes may be shared between related points and lines (spatial join).

Configuration

Input Ports

This transformer accepts features with line geometry.

Output Ports

Combined line and path features are output via this port, as are any untouched input line features.

Features with geometry other than valid line geometry are output via this port.

Rejected features will have an fme_rejection_code attribute with one of the following values:

INVALID_GEOMETRY_TYPE
INVALID_GEOMETRY_VERTICES

Rejected Feature Handling: can be set to either terminate the translation or continue running when it encounters a rejected feature. This setting is available both as a default FME option and as a workspace parameter.

Parameters

Combine On Attributes

Specify any attributes to be used for grouping lines to be combined.

Junctions

Select a method for handling multiple lines meeting at the same node:

Ignore Attribute Values If more than two lines meet at a node, they will all terminate at the node.

Consider Attribute Values

If more than two lines with the same attributes meet at a node, they will terminate at the node. Unique pairs of lines with the same attributes will carry on through the junction.

See Junctions, Intersections, and Crossings above.

Input Feature Topology

Select a method for handling features that intersect mid-line:

End noded

Only the start and end points will be considered for combining lines, and other vertices will be ignored.

Vertex noded

All vertices will be considered when combining lines.

See Junctions, Intersections, and Crossings above.

Accumulation Mode

Specify how attributes are accumulated on combined lines:

Drop Incoming Attributes

The output feature will not preserve any input attributes.

Merge Incoming Attributes

The output feature will merge all input attributes.

Use Attributes From One Feature

The output feature will receive attributes from only one input feature.

Generate List

When enabled:

List Name

Enter a List Name to be created on each output feature, containing an element for each input feature which contributed to that geometry.

Note  List attributes are not accessible from the output schema in FME Workbench unless they are first processed using a transformer that operates on them, such as ListExploder or ListConcatenator. Alternatively, AttributeExposer can be used.

Add To List

All Attributes: Every attribute from all input features that created an output feature will be added to the list specified in List Name.

Selected Attributes: Only the attributes specified in the Selected Attributes parameter will be added to the list specified in List Name.

Selected Attributes

The attributes to be added to the list when Add To List is Selected Attributes.

Direction Output Attribute Name

Name the optional attribute to include in the list, which indicates whether the direction of that input feature has been preserved (using same) or reversed (using opposite) in the output feature.

Preserve Orientation

Specify whether or not lines can be reversed in order to create longer lines.

  • No: Lines may be reversed.

  • Yes: Line may not be reversed.

Break On Loops

Select a method for handling any closed line features (input or output) where the start and end x and y coordinates are the same.

  • Yes: Lines that form a ring and do not interact with any other lines are split at two arbitrary end vertices of the original input.

  • No: Lines that form a ring and do not interact with any other lines are combined into a single linear feature whose start and end point is the same. The geometry type is line (not polygon). A LineCloser could be used to convert them to areas.

Consider Node Elevation

Select whether or not z values are to be considered when matching nodes:

  • Yes: z values must match.

  • No: z values are not considered in matching position.

See Z Values above.

Connect Z Mode

When Consider Node Elevation is No, select a method for determining z values when combining nodes that differ.

Select a method.

When viewed in 2D (ignoring Z), a path (which may define the border of a polygon) may appear to be closed as shown in the left figure below. This same path, when viewed in 3D, may appear to be open as shown in the right figure below.

To specify how (and if) paths should be closed in 3D, select one of the listed modes.

Mode

Description

Example
Extend The Curve is extended so that all vertices are left at their original location.
Average Subsequent vertices that are not connected, but share an x and a y value are combined into one vertex, whose Z value is the average of the original two.
First Wins Subsequent vertices that are not connected, but share an x and a y value are combined into one vertex, whose Z value is taken from the first encountered vertex.
Last Wins Subsequent vertices that are not connected, but share an x and a y value are combined into one vertex, whose Z value is taken from the last encountered vertex.
Ignore Z values are ignored. No change is made to the way the nodes are connected.

Preserve Lines as Path Segments

Specify whether combined lines should be path geometry rather than line geometry:

  • Yes: All input lines are preserved as discrete line segments within a complex path, including starting and ending points (pseudonodes are not removed).

  • No: Output geometry is determined by input geometry, defaulting to line unless path is necessary.

See Output Lines and Paths above.

Aggregate Handling

Select how aggregate geometries are to be handled:

  • Deaggregate: Decompose aggregates into their individual components.

  • Reject: Do not process aggregates and output them via the <Rejected> port.

Editing Transformer Parameters

Using a set of menu options, transformer parameters can be assigned by referencing other elements in the workspace. More advanced functions, such as an advanced editor and an arithmetic editor, are also available in some transformers. To access a menu of these options, click beside the applicable parameter. For more information, see Transformer Parameter Menu Options.

Defining Values

There are several ways to define a value for use in a Transformer. The simplest is to simply type in a value or string, which can include functions of various types such as attribute references, math and string functions, and workspace parameters. There are a number of tools and shortcuts that can assist in constructing values, generally available from the drop-down context menu adjacent to the value field.

Using the Text Editor

The Text Editor provides a convenient way to construct text strings (including regular expressions) from various data sources, such as attributes, parameters, and constants, where the result is used directly inside a parameter.

Text Editor

Using the Arithmetic Editor

The Arithmetic Editor provides a convenient way to construct math expressions from various data sources, such as attributes, parameters, and feature functions, where the result is used directly inside a parameter.

Arithmetic Editor

Conditional Values

Set values depending on one or more test conditions that either pass or fail.

Parameter Condition Definition Dialog

Content

Expressions and strings can include a number of functions, characters, parameters, and more.

When setting values - whether entered directly in a parameter or constructed using one of the editors - strings and expressions containing String, Math, Date/Time or FME Feature Functions will have those functions evaluated. Therefore, the names of these functions (in the form @<function_name>) should not be used as literal string values.

String Functions

These functions manipulate and format strings.

Special Characters

 A set of control characters is available in the Text Editor.

Math Functions

Math functions are available in both editors.
Date/Time Functions Date and time functions are available in the Text Editor.

Math Operators

These operators are available in the Arithmetic Editor.

FME Feature Functions

These return primarily feature-specific values.

FME Parameters

FME and workspace-specific parameters may be used.
Creating and Modifying User Parameters Create your own editable parameters.

Dialog Options - Tables

Transformers with table-style parameters have additional tools for populating and manipulating values.

Row Reordering

Enabled once you have clicked on a row item. Choices include:

  • Add a row
  • Remove a row
  • Move current row up one
  • Move current row down one
  • Move current row to top
  • Move current row to bottom

Cut, Copy, and Paste

Enabled once you have clicked on a row item. Choices include:

  • Cut a row - delete and copy to clipboard
  • Copy a row to the clipboard
  • Paste a row from the clipboard

Cut, copy, and paste may be used within a transformer, or between transformers.

Filter

Start typing a string, and the matrix will only display rows matching those characters. Searches all columns. This only affects the display of attributes within the transformer - it does not alter which attributes are output.

Import

Import populates the table with a set of new attributes read from a dataset. Specific application varies between transformers.

Reset/Refresh

Generally resets the table to its initial state, and may provide additional options to remove invalid entries. Behavior varies between transformers.

Note: Not all tools are available in all transformers.

Reference

Processing Behavior

Group-Based

Feature Holding

Yes
Dependencies None
Aliases PseudoNodeRemover, LineJoiner
History  

FME Community

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Examples may contain information licensed under the Open Government Licence – Vancouver and/or the Open Government Licence – Canada.