Fill Polygon Gaps

The Fill Polygon Gaps tool automatically fills gaps between barangay polygons by assigning uncovered areas to the correct neighboring polygon. It supports a preview-before-apply workflow, allowing you to inspect proposed gap fills before committing changes.

Access

• Processing Toolbox: GMD Pipeline → 1Map → Fill Polygon Gaps
• Algorithm ID: gmd_pipeline:fill_polygon_gaps

When to Use

Use this tool when:

• The MBI Checker has identified gaps between barangay boundaries
• You need to assign uncovered areas to the correct adjacent barangay
• You want to preview gap fills before applying them to the data

Parameters

Parameter	Type	Description
Input Layer	Vector Layer (Polygon)	The barangay boundary polygon layer containing gaps
Label Field	Field	The attribute field used to identify each polygon (e.g., barangay name)
Polygon Identifier Value	Custom Dropdown	Select the specific polygon to fill gaps for — populated dynamically from the label field
Extent Mode	Dropdown	Choose between Manual Extent or Extent Layer to define the working area
Extent	Extent	Manual extent for the analysis area (when using Manual Extent mode)
Extent Layer	Vector Layer	A layer whose extent defines the analysis area (when using Extent Layer mode)

How It Works

1. Extent Definition — The tool determines the working area either from a manual extent or from the bounding box of an extent layer.
2. Feature Filtering — Only polygons intersecting the defined extent are considered, improving performance for large datasets.
3. Gap Detection — The tool identifies empty areas between the selected polygon and its neighbors within the extent.
4. Gap Assignment — Gaps are assigned to the nearest polygon based on spatial proximity.
5. Preview — Results are displayed as a categorized layer so you can inspect the proposed assignments.
6. Apply — Once satisfied, apply the changes to update the polygon boundaries.

Dynamic Dropdown

The Polygon Identifier Value parameter uses a custom widget that dynamically updates its choices based on:

• The selected Input Layer
• The selected Label Field
• The current Extent (only values from features intersecting the extent are listed)

This makes it easy to work with specific areas without scrolling through large value lists.

Output

• A gap-filled polygon layer with categorized styling showing which gaps were assigned to which barangay
• Color-coded results for easy visual validation

TIP

Use the Extent Layer mode when you want to focus on a specific city or municipality. Load the municipal boundary and select it as the extent layer — only barangays within that area will be processed.

WARNING

Always review the gap fill results carefully before committing changes. Automated gap assignment is based on spatial proximity and may not always match the intended administrative boundary.