AreaCalculator

Calculates the planar or sloped area of polygon geometries and adds the results as attributes.

Typical Uses

Retrieving area values as attributes

How does it work?

The AreaCalculator receives features with any type of geometry, and calculates areas as follows:

Area polygons (2D) - plane area
Area polygons with z values - plane or sloped area
Raster - plane area of raster extents
3D object - cumulative area of all surfaces
Other geometries (including point clouds) - receive an area of zero (0)

Area values are stored in a specified attribute.

Units are square ground units according to the feature's coordinate system. A multiplier may be applied to scale the values and convert to different units of measure.

Aggregates are supported.

Examples

Usage Notes

Alternatively, the @Area() function can be used in expressions to calculate area values.
In general, features in a geographic projection (lat/long) should be reprojected to an appropriate coordinate system before calculating areas. The Reprojector or CommonLocalReprojector may be useful.

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.	Performs an area-on-area overlay (intersection of polygons) so that all input areas are intersected against each other and resultant area features are created and output. The resultant areas can accumulate attribute from any overlapping polygons.
LineOnAreaOverlayer	Find intersections between lines and polygons, splitting either where they intersect.	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).
PointOnAreaOverlayer	Identify points that fall within polygons, and share attributes between them.	Performs a point-in-polygon overlay. Points may receive containing area attributes, and areas may receive contained point attributes (spatial join).

Configuration

Input Ports

Output Ports

Note Feature order may change in relation to other output ports. Feature order per port is maintained.

Parameters

General

Type

Select the type of area calculation to perform:

Plane Area (default): Area calculated from x and y coordinates only.
Sloped Area: If polygon features have z coordinates, they are included in the area calculation.

Raster and full 3D geometry (solid and mesh) area calculations are not affected by this choice. Raster area is the raster extents (plane area) and 3D area is the cumulative area of all 3D surfaces.

Multiplier

Specify a value to optionally scale the area values. Default is 1.

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

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.

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

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.

Reference

Processing Behavior	Feature-Based
Feature Holding	No
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.