FME Transformers: 2024.1

Categories
Geometries

Geometries

Related Transformers
LineCloser
LineCombiner
LineExtender
PathBuilder
Categories
Geometries

Geometries

Related Transformers
LineCloser
LineCombiner
LineExtender
PathBuilder

LineBuilder

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

Jump to Configuration

Typical Uses

  • Connecting points to form a line
  • Connecting multiple lines into longer, continuous lines

How does it work?

The LineBuilder receives features with point and/or line geometry, and connects them in the order received, producing line or area geometry.

Both the order in which the features enter the transformer and the orientation of any line geometry received are honored. Gaps between line features are connected, and duplicate points may be either processed or ignored.

Z values are supported. If some input features have z values and others do not, those without are assigned a z value of zero (0). Features with matching x and y coordinates but differing z values are not considered duplicates.

If the output feature is closed (the first and last x and y coordinates are the same), an area is output whether or not the z values match.

Features may be grouped by attribute values to produce multiple outputs.

Attributes may be merged, dropped, or collected as List Attributes.

Examples

In this example, we have a set of point features captured by GPS along a route. We want to create a line from these sequential points.

The features are routed into a LineBuilder.

In the parameters dialog, the default settings are used.

A single line feature is output, connecting all of the input points in the order they were received.

Usage Notes

  • The Sorter may be useful for ordering features before using the LineBuilder.
  • As the LineBuilder fills in gaps between features, it can produce unexpected results if the input features are not sorted correctly. To combine adjoining lines (without creating new geometry to connect gaps), use a LineCombiner.
  • The CoordinateSwapper may be useful in specific cases.

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

Converting linear features into areas.

Converts a linear feature to an area by connecting the end point to the start point.

LineExtender

Extending linear geometry.

Extends line, arc, or path features at both ends by a specified length.

Chopper

Chopping features into smaller features, breaking them at their existing vertices.

Chops line, arc, path, or area features into smaller features based on number of vertices or approximate length.

PathSplitter

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

Splits path geometry into its component line and/or arc segments.

Snipper

Shortening linear geometry.

Shortens linear geometry by cutting off the ends.

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 point and line geometries.

Output Ports

If the resulting feature is a single point, it will be output through this port.

If the resulting feature does not begin and end at the same point, it is output through this port.

If the resulting feature forms a ring (begins and ends at the same point), it is output through this port.

Any features that are not points or lines are output through this port.

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

INVALID_GEOMETRY_TYPE

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

Group By

The default behavior is to use the entire set of input features as the group. This option allows you to select attributes that define which groups to form – each set of features that have the same value for all of these attributes will be processed as an independent group.

If only one point feature was received with a given value for the Group By value, it will be output as a Point.

If the feature output forms a ring (begins and ends at the same point), it is output as a Polygon.

Anything else is output as a Line.

Complete Groups

Select the point in processing at which groups are processed:

When All Features Received

This is the default behavior. Processing will only occur in this transformer once all input is present.

When Group Changes (Advanced)

This transformer will process input groups in order. Changes of the value of the Group By parameter on the input stream will trigger processing on the currently accumulating group. This may improve overall speed (particularly with multiple, equally-sized groups), but could cause undesired behavior if input groups are not truly ordered.

There are two typical reasons for using When Group Changes (Advanced) . The first is incoming data that is intended to be processed in groups (and is already so ordered). In this case, the structure dictates Group By usage - not performance considerations.

The second possible reason is potential performance gains.

Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains).

Sorting becomes more difficult according to the number of data streams. Multiple streams of data could be almost impossible to sort into the correct order, since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group. In this case, using Group By with When All Features Received may be the equivalent and simpler approach.

Note  Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.

As with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains.

Remove Duplicate Points

If Yes, duplicate coordinates from input features are removed. That is, if two point features, both at (0,0,0) are input, one point at (0,0,0) is output. If No, duplicate coordinates from input features are not removed. That is, if two point features at (0,0,0) are input, a line is output with two coordinates, both at (0,0,0).

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, in order of appearance.

This parameter can also be used to preserve attributes from input features.

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.

Editing Transformer Parameters

Transformer parameters can be set by directly entering values, using expressions, or referencing other elements in the workspace such as attribute values or user parameters. Various editors and context menus are available to assist. To see what is available, click beside the applicable parameter.

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.

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.

Table Tools

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.

For more information, see Transformer Parameter Menu Options.

FME Community

The FME Community is the place for demos, how-tos, articles, FAQs, and more. Get answers to your questions, learn from other users, and suggest, vote, and comment on new features.

Search for all results about the LineBuilder on the FME Community.

Keywords: "point joiner" "line creator" PointConnector