PointOnLineOverlayer

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).

Jump to Configuration

Typical Uses

Splitting lines where they overlay points
Identifying lines that intersect with a point
Identifying points that fall on a line

How does it work?

The PointOnLineOverlayer compares points and lines, splitting the lines where a point falls on (or within a specified distance of) the lines. Each resulting new line may receive the attributes of the points that matched the original line, and points may receive attributes from the lines (a spatial join). Features (points and lines) also receive a count of the number of matches encountered.

Aggregates can either be deaggregated before processing or rejected. Intersections between linear features are not computed.

Examples

Usage Notes

Where point geometries are expected, Point Cloud geometries are not supported.
Chopped Lines output via the Line output port receive the attributes of all points that matched the original input line (if a list is enabled). All points that the original line encountered are included - not only the endpoints of the new line segment.
To obtain attributes from points matching only the ends of the new line features, use a second transformer (consider another PointOnLineOverlayer, or a NeighborFinder).

Z Values and Measures

If the input Line features have measures and/or 3D coordinates, measures and elevations (z values) are interpolated and assigned to points according to the selections made in the Attribute Accumulation parameters.

If Attribute Accumulation Mode is set to Drop Incoming Attributes, the measures and z values will be ignored. If it is set to Merge, Prefix, or Replace with Single Incoming, the appropriate values will be calculated and assigned to the points. If a z value is added to a 2D point, it will become 3D.

Choosing a Spatial Transformer

Many transformers can assess spatial relationships and perform spatial joins - analyzing topology, merging attributes, and sometimes modifying geometry. Generally, choosing the one that is most specific to the task you need to accomplish will provide the optimal performance results. If there is more than one way to do it (which is frequently the case), time spent on performance testing alternate methods may be worthwhile.

To correctly analyze spatial relationships, all features should be in the same coordinate system. The Reprojector may be useful for reprojecting features within the workspace.

Spatial Transformers Comparison Matrix

Transformer	Can Merge Attributes	Alters Geometry	Counts Related Features	Creates List	Supported Types*	Recommended For
SpatialFilter	Yes	No	No	No	Point Text Curve Area	Testing for the existence of spatial relationships between two sets of features, and routing them according to whether they pass or fail the test(s).
SpatialRelator	Yes	No	Yes	Yes	Point Text Curve Area	Identifying the nature of spatial relationships between two sets of features.
AreaOnAreaOverlayer	Yes	Yes	Yes	Yes	Area	Finding polygon overlaps and extracting them into new geometry.
LineOnAreaOverlayer	Yes	Yes	Yes	Yes	Curve and Area	Finding intersections between lines and polygons, and splitting the lines where they intersect with the polygons.
LineOnLineOverlayer	Yes	Yes	Yes	Yes	Curve	Finding intersections between line features, splitting them, and generating new line geometry as well as points representing the intersections.
PointOnAreaOverlayer	Yes	No	Yes	Yes	Point and Area Text and Area	Identifying points that fall within polygons, and merging attributes between them
PointOnLineOverlayer	Yes	Yes	Yes	Yes	Point and Curve Text and Curve	Identifying where points fall on lines, and splitting the lines into new geometry.
PointOnPointOverlayer	Yes	No	Yes	Yes	Point Text	Identifying points in the same location (within a tolerance), and merging attributes between them.
Intersector	Yes	Yes	Yes	Yes	Point Text Curve Area	Finding intersections between all input features, regardless of geometry (including self-intersections), splitting features, and creating new geometry.
Clipper	Yes	Yes	No	No	Point Text Curve Area Surface Solids Raster Point Cloud	Comparing features against a set of Clipper features, and splitting the features at or along the Clipper boundaries. Outputs both new and untouched geometry, identified as either Inside or Outside the Clipper.
NeighborFinder	Yes	In some cases	No	Yes	Point Text Curve Area	Identifying the nearest other feature(s) to each feature being considered, either in another set of features or within the same feature set.
TopologyBuilder	Yes	Yes	No	Yes	Point Text Curve Area	Analyzing spatial relationships between features to compute topology, splitting features and creating new geometry representing topologically significant nodes, edges, and faces, with associated attributes.

* Note that Curve includes Lines, Arcs, and Paths. Area includes Polygons, Donuts, and Ellipses.

Configuration

Input Ports

Output Ports

Parameters

Group Processing

Group By

The default behavior is to use the entire set of features as the group. This option allows you to select attributes that define which groups to form.

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.

General

Point Tolerance	The Point Tolerance value is compared to the distance from the lines to the points, and the lines will be segmented if the distance is less than or equal to the Point Tolerance value. When such a match occurs, the attributes of the segmented lines are merged with the points and the attributes of the points are merged with the lines.
Aggregate Handling	Choose 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.
Merge Measures	If Yes, any measures that exist on a line will be added to matching points. Measure values are determined according to the Treat Measures As parameter. If both point and line have measures of the same name, the point's values will be overwritten by the line's values. If No, no measures will be copied, and any existing measures (on points or lines) will be output unchanged.
Treat Measures As	This parameter determines how measures are computed: at new intersection locations on lines, and when adding measures to points if Merge Measures is Yes. Continuous: The new measure value will be calculated, interpolating based on the nearest measures. Discrete: The new measure value will be copied from the nearest measure.

Attribute Accumulation

If attributes on the incoming and original feature share the same name, but are not geometry attributes that start with fme_, then they are deemed conflicted.

Note: On the PointOnLineOverlayer, Attribute Accumulation applies to the measures on a point in a similar way to how it applies to the attributes on a feature.

If measures on the point and line share the same name, then they are deemed conflicted.

The resolution of conflicted measures on points occurs in the same manner as the resolution of conflicted attributes on features. It is resolved according to the Accumulation Mode and Conflict Resolution values.

Merge Attributes

Accumulation Mode

Merge Incoming: The original feature will retain all of its own un-conflicted attributes, and will additionally acquire any un-conflicted attributes that the incoming feature has. This mode will handle conflicted attributes based on the Conflict Resolution parameter.

Prefix Incoming: The original feature will retain all of its own attributes. In addition, the original will acquire attributes reflecting the incoming feature’s attributes, with the name prefixed with the Prefix parameter.

Replace with Single Incoming: The original feature will have all of its attributes removed, except geometry attributes that start with fme_. Then, all of the attributes from one (arbitrary) incoming feature will be placed onto the original.

Conflict Resolution

Use Original: If a conflict occurs, the original values will be maintained.

Use Incoming: If a conflict occurs, the values of the incoming will be transferred onto the original.

Prefix

If the Accumulation Mode parameter is set to Prefix Incoming, this value will prefix attributes and measures that are being added to the original feature from the incoming feature.

Generate List on Output ‘Point’

When enabled, adds a list attribute to the Point output features, and the attributes of each line matching an output point are added to that point's list.

‘Point’ List Name

Enter a name for the list attribute.

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 'Point' List

All Attributes: All attributes will be added to the output Point features.

Selected Attributes: Enables the Selected Attributes parameter, where specific attributes may be chosen for inclusion.

Selected Attributes

Enabled when Add To 'Point' List is set to Selected Attributes. Specify the attributes you wish to be included.

Generate List on Output ‘Line’

When enabled, adds a list attribute to the Line output features, and the attributes of each point matching an original input line are added to each output line created from it.

‘Line’ List Name

Enter a name for the list attribute.

Add To 'Line' List

All Attributes: All attributes will be added to the output Line features.

Selected Attributes: Enables the Selected Attributes parameter, where specific attributes may be chosen for inclusion.

Selected Attributes

Enabled when Add To 'Line' List is set to Selected Attributes. Specify the attributes you wish to be included.

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.

How to Set Parameter Values

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.

Content Types

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.

Table Tools

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
Aliases
History

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