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    AreaGapAndOverlapCleaner

    Repairs area topologies by resolving gaps and overlaps between adjacent areas.An overlap occurs where two or more areas intersect each other, creating a region covered by multiple areas. A gap occurs where two or more areas fail to meet at a boundary.

    Jump to Configuration

    Typical Uses

    • Cleaning topology errors in a polygon coverage to create a single, continuous surface.

    How does it work?

    The AreaGapAndOverlapCleaner resolves the differences between adjacent areas, creating a topologically clean shared boundary by dissolving overlaps and filling in gaps between the polygons.

    These operations are generally carried out within a specifiedTolerance- the distance, in ground units - within which gaps are candidates for repair.

    All processing within theTolerancedistance is automated. Processing outside of theToleranceis performed according to theRepair Methodparameter, which provides options for determining which polygons take precedence.

    All overlaps are resolved, whether they fall within the tolerance or not. Gaps outside tolerance may optionally be resolved.

    Tolerancemay be set to any number zero (0) or greater, or calculated automatically. SettingToleranceto zero will result in all overlaps and gaps being processed according to theRepair Method.

    While all overlaps will always be processed, gaps outside theTolerancewill only be processed if theFill All Gapsparameter is set toYes.

    Processing Behavior and Tolerance

    Within Tolerance

    Outside Tolerance
    Overlaps Automatic According to Repair Method
    Gaps Automatic Not processed
    Gaps whenFill All Gaps=Yes Automatic According to Repair Method

    Example

    Usage Notes

    • Requires valid area geometries. For example, self-intersecting, or degenerate areas will not be properly repaired.
    • If a single area is input, it will be output unchanged.
    • The AreaGapAndOverlapCleaner may create spikes when merging large overlaps to adjacent areas. However, spikes smaller than the tolerance will never be created. If these spikes are not desired, try increasing the tolerance.
    • Donut holes, if not filled by another area, are considered gaps in the coverage. They may be filled in if overlapped.

    配置

    Input Ports

    ClosedInput

    Only area geometries are accepted as input.

    Output Ports

    ClosedRepaired

    Features that have been cleaned are output via this port.

    ClosedRemnants

    Geometries that collapsed within tolerance will be output via theRemnantsport. Additionally, features that did not have any geometry left after overlap resolution will also be output via this port with null geometries.

    Closed

    Features with invalid geometries will be rejected and output via this port. Additionally, if theRepair Methodparameter isPriority (Edge Preserving)orPriority (Area Enlarging)特性与无效的优先级属性lso be rejected via this port.

    Rejected features will have anfme_rejection_codeattribute with one of the following values:

    INVALID_GEOMETRY_TYPE

    INVALID_PARAMETER_PRIORITY_ATTRIBUTE

    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 defaultFME optionand as aworkspace parameter.

    Parameters

    ClosedTransformer
    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.
    Group By Mode

    Process At End (Blocking): This is the default behavior. Processing will only occur in this transformer once all input is present.

    Process 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.

    ClosedConsiderations for UsingGroup By

    There are two typical reasons for usingProcess 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 aSQL ORDER BYstatement) 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 aGroup By价值需要加勒比海盗ive before any features (of any feature type or dataset) belonging to the next group. In this case, usingGroup BywithProcess At End (Blocking)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.
    ClosedParameters
    Tolerance

    The maximum distance between geometries in 2D for inclusion in automated processing.

    IfAutomatic, an appropriate tolerance will be assigned based on the input features. Automatic Tolerance values tend to be small, and can assist in preventing issues caused by using excess precision.
    Aggregate Handling

    Choose how aggregate geometries are to be handled.

    Deaggregate:Decompose aggregates into their individual components. With this setting, the transformer might output more features than were given as inputs.

    Reject:Do not process aggregates and output them via the port.
    ClosedZ and Measures Parameters
    Connect Z Mode

    If applicable, select a method for handling z values.

    ClosedConnect Z Mode

    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.
    Measures/Z Conflict Value

    This parameter specifies how to deal with geometries that have a measure, but are missing at least one value, or that have z values, but are missing at least one value.

    None (Drop Values): Remove incomplete measures or z values.

    Compute: Look at the values on either side of the missing value, and compute an estimate.

    Custom Value: The missing values are filled in with the specified custom default value.
    Treat Measures as When using the Compute mode to compute missing measure values, measures can be consideredContinuous, and linearly interpolated from their neighbors, or they can beDiscrete, and taken exactly from the nearest neighbor.
    ClosedAdvanced Parameters
    Fill All Gaps

    Yes: All gaps in the coverage will be filled.

    No: Only gaps within the tolerance will be filled.
    Repair Method

    Specifies how to resolve gaps and overlaps that fall outside the tolerance.

    Given the following input:

    Longest Boundary The polygon with the longest border length to the conflict will be chosen.
    Random The polygon to merge a conflicting region into will be selected at random.
    Priority (Edge Preserving) 允许个人polyg控制的优先级ons in the repair process. The boundary of the higher priority polygon is preserved in this mode. Gaps between polygons will be assigned to the lower priority neighboring polygon, and overlaps will be assigned to the higher priority neighboring polygon. This method is used in conjunction with thePriority Attributeparameter.

    Yellow: Higher Priority
    Blue: Lower Priority
    Priority (Area Enlarging) 允许个人polyg控制的优先级ons in the repair process. The area of the higher priority polygon will be enlarged in this mode. Gaps and overlaps between polygons will be assigned to the higher priority neighboring polygon. This method is used in conjunction with thePriority Attributeparameter.

    Yellow: Higher Priority
    Blue: Lower Priority
    Priority Attribute

    ThePriority Attributeshould be a non-negative integer value, with 0 meaning highest priority. It is enabled when theRepair Methodparameter isPriority (Edge Preserving)orPriority (Area Enlarging).

    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, clickbeside the applicable parameter. For more information, seeTransformer 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.

    ClosedHow 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.

    ClosedContent 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.

    Reference

    ClosedRelated Transformers

    AreaOnAreaOverlayer

    Snapper

    Processing Behavior

    Group-Based

    Feature Holding

    Yes
    Dependencies
    FME Licensing Level FME Professional Edition and above
    Aliases SliverRemover
    历史
    Categories

    Data Quality

    Geometries

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    Examples may contain information licensed under the Open Government Licence – Vancouver