Dissolver

Combines overlapping and/or adjacent areas into larger contiguous areas by removing shared and interior edges.

Typical Uses

Simplifying geometry
Combining areas for statistical analysis

How does it work?

The Dissolver receives features with area geometry and combines them wherever they touch or overlap. Shared edges and linear boundaries inside overlapping areas are removed from the resulting polygon, and output separately.

Input feature attributes may be optionally accumulated as a list attribute. Statistics can be calculated on numeric attributes, including sum, average, and weighted average (by area). The number of polygons dissolved to create each output area can be stored in an attribute.

Gaps and slivers that occur where adjacent areas are not perfectly identical are considered a match to dissolve if they fall within a specified tolerance.

Aggregates may be either deaggregated or rejected.

Z values are supported.

	Input	Dissolved	Remnants
Shared Edges
Overlaps
Donut Polygons

Examples

Usage Notes

Unexpected results often indicate issues with the input data.

Creating and Modifying Area Features

These transformers work with polygons in a variety of ways.

Area Transformers Comparison

Transformer	Use this to...	Transformer Description
Creator	Create one or more new features with area geometry (when Geometry Object is Polygon).	Creates features using the parameters supplied, and sends them into the workspace for processing.
AreaBuilder	Create areas from topologically connected lines where they form closed shapes.	Creates polygons from topologically correct linear features.
LineCloser	Create areas from individual linear features.	Converts a linear feature to an area by connecting the end point to the start point.
Dissolver	Combine touching or overlapping areas to create larger areas.	Combines overlapping and/or adjacent areas into larger contiguous areas by removing shared and interior edges.
AreaCalculator	Calculate areas.	Calculates the planar or sloped area of polygon geometries and adds the results as attributes.
AreaGapAndOverlapCleaner	Clean up overlaps and gaps to create contiguous coverage.	Repairs area topologies by resolving gaps and overlaps between adjacent areas.
AreaAmalgamator	Generalize areas.	Generalizes area geometry by connecting and combining neighboring features and/or filling in holes and details.
DonutBridgeBuilder	Convert donut areas to non-donut areas.	Adds internal edges to connect donut holes to the outer shell, producing a non-donut polygon.
DonutBuilder	Convert areas within areas to donut holes.	Cuts holes in area features where they fully enclose another area, creating donut polygons.
DonutHoleExtractor	Separate donut areas into their parts.	Separates donut polygons into outer shell and hole polygons.
HoleCounter	Count the number of holes in a donut area.	Retrieves the number of holes in donut polygons, storing the result as an attribute.
AreaOnAreaOverlayer	Find polygon overlaps and extract them into new geometry.	Overlays areas on areas, intersecting geometry and sharing attributes.
LineOnAreaOverlayer	Find intersections between lines and polygons, splitting either where they intersect.	Overlays lines and areas, intersecting geometry and sharing attributes.
PointOnAreaOverlayer	Identify points that fall within polygons, and share attributes between them.	Overlays points and areas, sharing attributes.

Configuration

Input Ports

Output Ports

Parameters

Group Processing (Optional)

General

Attribute Accumulation

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.

How to Set Parameter Values

Dialog Options - Tables

For more information, see Transformer Parameter Menu Options.

Reference

Processing Behavior	Group-Based
Feature Holding	Yes
Dependencies	None
Aliases
History

FME Community

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

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.

Dissolver

Typical Uses

How does it work?

Examples

Usage Notes

Creating and Modifying Area Features

Configuration

Input Ports

Output Ports

Parameters

Editing Transformer Parameters

Defining Values

Using the Text Editor

Using the Arithmetic Editor

Conditional Values

Content

Table Tools

Reference

FME Community