MBI Checker

The MBI Checker (Map-Based Inventory Checker) is the core quality assurance tool for detecting gaps and overlaps in barangay polygon boundaries. It cross-references boundary polygons with building point layers to produce a comprehensive topology report.

Access

• Processing Toolbox: GMD Pipeline → 1Map → MBI Checker
• Algorithm ID: gmd_pipeline:gaps_overlaps_checker

When to Use

Use this tool when you need to:

• Verify that barangay boundaries have no overlapping areas
• Check for gaps between adjacent barangay polygons
• Validate boundary integrity before submission
• Generate MBI report layers for review

Parameters

Parameter	Type	Description
Barangay Polygon Layer(s)	Multiple Vector Layers (Polygon)	Select one or more barangay boundary polygon layers to check
Building Point Layer(s)	Multiple Vector Layers (Point)	Select one or more building point layers for reference
Analysis to Run	Dropdown	Choose between: Overlaps and Gaps, Overlaps Only, or Gaps Only
Export MBI layers as GPKG	Checkbox	If checked, exports results to C:\PSA-GIS\2026 1Map\Preliminary Output

Analysis Modes

Overlaps and Gaps (Default)

Runs both overlap detection and gap detection in a single pass. Use this for a complete boundary validation.

Overlaps Only

Only detects areas where two or more barangay polygons overlap. Useful when gaps have already been resolved and you need to focus on overlapping boundaries.

Gaps Only

Only detects empty areas between barangay polygons. Useful when overlaps have already been resolved and you need to focus on missing boundary coverage.

How It Works

1. Layer Merging — Selected barangay layers are merged into a single dataset, with field schemas harmonized via refactoring.
2. Overlap Detection — The tool identifies areas where polygon geometries intersect, producing overlap polygons.
3. Gap Detection — The tool computes the boundary extent and identifies uncovered areas between polygons.
4. Styling — Output layers are automatically styled using the included MBI checker QML style for easy visual interpretation.
5. Export (optional) — Results can be saved as GPKG files for offline review or sharing.

Output

The tool produces styled layers that are added to your QGIS project:

• Overlap layers — Polygons showing areas of overlap between barangay boundaries
• Gap layers — Polygons showing areas with no boundary coverage

TIP

When the Export MBI option is enabled, the layers are also saved as GeoPackage files in the output directory. This makes it easy to share results with supervisors or other team members.

Best Practices

1. Load all relevant layers first — Make sure all barangay polygon layers and building point layers are loaded in your QGIS project before running the tool.
2. Start with "Overlaps and Gaps" — Run the full analysis first to get a complete picture of boundary issues.
3. Fix overlaps before gaps — Overlaps should generally be resolved first, as fixing overlaps can sometimes create or eliminate gaps.
4. Re-run after fixes — After making boundary corrections, re-run the checker to verify that all issues have been resolved.