Run Analysis

The Run Analysis tool performs comprehensive boundary topology and discrepancy detection across LGU and PSA polygon layers and building points. It first resolves a single authoritative boundary per city/municipality — deduplicating repeated submissions, giving precedence to the LGU's latest submission over the PSA reference, and labeling every remaining non-LGU polygon's source as PSA — then consolidates all Gaps/Overlaps/Disputed findings against that boundary into a unified Reference MBI layer named ref_mbi_cases.

Access

• Processing Toolbox: GMD Pipeline → 1Map → Run Analysis
• Algorithm ID: gmd_pipeline:run_analysis

When to Use

Use this tool when:

• Establishing the baseline Reference MBI cases layer (ref_mbi_cases) for a municipality or province.
• Generating the required reference input layer consumed by the MBI Validator tool.
• Resolving LGU vs PSA boundary precedence: the LGU layer is treated as the latest submission, so any city/municipality with at least one LGU polygon uses LGU boundaries exclusively; a city/municipality with no LGU submission falls back to PSA.
• Cleaning up duplicate boundary submissions (the same barangay digitized twice, or the same area present in more than one selected input layer) before they can produce false gap/overlap findings.
• Detecting sliver gaps between adjacent barangay polygons while automatically excluding already-recorded disputed territories.
• Identifying boundary overlaps across different administrative levels (Inter-Region, Inter-Province, Inter-City/Municipality, Inter-Barangay, or Within-Barangay).
• Extracting contested boundary claims tagged as disputed in LGU datasets.
• Setting up pre-configured attribute table dropdown widgets (ValueMap for mbi_status) for provincial field validation.

Parameters

Inputs

Parameter	Type	Description
Select Polygon Layer(s)	Multiple Layers (Polygon)	One or more vector polygon layers representing barangay boundaries from LGU and PSA datasets. Required.
Select Building Point Layer(s)	Multiple Layers (Point)	One or more point layers representing structures/buildings used to count intersecting points within each finding. Required.

Fixed Analysis Execution

All three boundary analyses (Gaps, Overlaps, and Disputed Areas) execute automatically as mandatory procedures. No manual analysis mode parameter is required.

Outputs

Output	Type	Description
2026_province_boundary	Vector Layer (MultiPolygon, In-Memory)	The resolved authoritative boundary set in EPSG:4326: rows sharing a geocode merged into one multipart feature, LGU polygons kept wherever an LGU submission exists for a city_mun (its PSA counterpart excluded), and every remaining non-LGU polygon explicitly labeled source = PSA. One row per geocode per source, with islets retained as parts of their barangay. Detection below runs on a single-part working copy of this same boundary.
ref_mbi_cases	Feature Sink (Polygon)	A consolidated polygon layer in EPSG:4326 containing all detected boundary findings categorized by mbi_type. Formatted with pre-configured attribute table editor widgets.

Output Layer Schema

The resulting ref_mbi_cases layer contains the following standardized attributes:

Field Name	Type	Access	Description
case_uuid	String	Read-Only	Unique UUID string assigned to each individual finding.
geocode	String	Editable	9-digit PSGC geocode associated with the primary reference polygon.
region	String	Read-Only	Region name or code.
province	String	Read-Only	Province name.
city_mun	String	Editable	City or municipality name.
barangay	String	Editable	Barangay name.
source	String	Read-Only	Data source provenance label (e.g. LGU or PSA; NULL for gaps).
mbi_level	String	Read-Only	Administrative boundary hierarchy level: Inter-Region, Inter-Province, Inter-City/Municipality, Inter-Barangay, or Within-Barangay.
involved_areas	String	Read-Only	Comma-separated list of all involved PSGC geocodes.
involved_bgys	String	Read-Only	Semicolon-separated list of all involved barangay and city/municipality names.
count_involved_areas	Integer	Read-Only	Total count of distinct administrative units participating in the finding.
mbi_type	String	Read-Only	Classification category: 1_Gap, 2_Overlap, or 3_Disputed.
num_bldg_pts	Integer	Read-Only	Count of intersecting building points falling within the finding polygon.
mbi_status	String	Editable	Status field equipped with a QGIS ValueMap dropdown widget: 1_Updated or 2_Pending.
mbi_remarks	String	Read-Only	System remarks populated automatically when an overlap touches a disputed polygon (For Review - Involves Disputed Area).
pso_remarks	String	Editable	Text field reserved for notes entered by Provincial Statistical Offices.
lgu_bgy_name	String	Editable	LGU-declared barangay name populated specifically for Disputed records (NULL for gaps/overlaps).

How It Works

1. Layer Pre-Processing and Coordinate Normalization:

   • Multiple input polygon and building point layers are refactored, merged, and projected to Web Mercator (EPSG:3857) for accurate metric area calculations and geometric topological operations.
   • Geometries are validated and repaired using geometry fixing algorithms. Multipart geometries are deliberately not exploded at this stage — the boundary is resolved and published first, so a barangay with an islet stays a single feature.

2. Merging Rows That Share a Geocode:

   • Every feature sharing a geocode + source is merged into one multipart feature, so geocode is unique per source in the published boundary.
   • Rows share a geocode for two different reasons, and the union handles both: a barangay submitted twice produces overlapping rows, whose union is that same area (nothing is double-counted even if the two submissions were digitized slightly differently); a barangay whose islet was stored as its own row produces disjoint rows, whose union keeps the islet as a second part instead of discarding it.
   • source stays in the key because LGU and PSA carry the same geocode for the same barangay — merging them here would pre-empt the precedence rule below.

3. Boundary Precedence Resolution:

   • The LGU layer is treated as the latest submission. For every city_mun where at least one polygon's source contains LGU, that city_mun's PSA polygon(s) are excluded and only the LGU polygon(s) are kept.
   • A city_mun with no LGU submission at all falls back to using its PSA polygon(s) unchanged.
   • Every non-LGU polygon that survives this step then has its source attribute explicitly set to PSA (overwriting a blank/NULL/other value), so downstream findings never carry an ambiguous source label.
   • The resolved boundary is repaired with native:fixgeometries before anything else happens to it, since merging rows by geocode unions geometries together and can leave a self-intersection behind. Both the published layer and the detection working copy inherit the repaired version.
   • The resulting authoritative set is reprojected to EPSG:4326 and published as 2026_province_boundary with multipart barangays intact — one row per geocode per source, so de-duplicating the table by geocode can never delete an islet.

4. Spatial Indexing & Attribute Extraction:

   • A separate single-part working copy of the resolved boundary is produced with multiparttosingleparts, used only by the detection steps below — it never reaches the published layer.
   • Spatial bounding box indexes (QgsSpatialIndex) and cached feature lookups are constructed for both that working copy and the building points.
   • Core administrative attributes (geocode, region, province, city_mun, barangay, boundary, source) are normalized into structured lookup records.

5. Disputed Territory Identification:

   • Polygons tagged with boundary = Contested or disputed markers are isolated.
   • Each contested area is converted to 3_Disputed in the output schema and its footprint is unioned in memory.

6. Overlap Detection Engine:

   • Pairs of intersecting polygons are detected using the spatial index.
   • The geometric intersection is computed, filtered to retain polygons with areas greater than 0.10 square meters, and tagged with administrative level hierarchy (mbi_level).
   • If either overlapping polygon is marked as disputed, mbi_remarks is automatically populated with For Review - Involves Disputed Area.
   • Intersecting building points within the overlap polygon are tallied into num_bldg_pts.

7. Gap Detection Engine:

   • Non-disputed boundary polygons are dissolved into a unified regional coverage.
   • Holes within the dissolved polygon coverage are filled, and a symmetric difference is computed between the filled coverage and the original dissolved coverage to extract internal void slivers.
   • The unioned footprint of all Disputed territories is subtracted from the candidate gap geometries, ensuring that contested territories are never duplicated as gaps.
   • Qualifying gap slivers are linked to adjacent participating barangays and assigned mbi_type = 1_Gap.

8. Output Layer Generation, Styling & Editor Widget Application:

   • All findings are transformed to WGS 84 (EPSG:4326) and added to the consolidated ref_mbi_cases layer.
   • Each finding is checked with isGeosValid() first and repaired with makeValid() if needed, since gap and overlap geometries come straight out of raw intersection and difference results and can be self-intersecting. A repair returning anything non-polygonal is discarded rather than written, so the layer's geometry type never changes; the number of repaired findings is reported in the execution log.
   • The layer post-processor (FieldWidgetPostProcessor) automatically loads and applies the embedded categorized QML style (ref_mbi_cases.qml), displaying distinct symbology and labeling for 1_Gap, 2_Overlap, and 3_Disputed cases.
   • Attaches ValueMap editor widgets to mbi_status (1_Updated, 2_Pending) and text input setups to remarks fields directly upon loading into QGIS.
   • Sets computed reference attributes to Read-Only (case_uuid, region, province, source, mbi_level, involved_areas, involved_bgys, count_involved_areas, mbi_type, num_bldg_pts, and mbi_remarks) to prevent accidental edits while keeping reviewer fields (geocode, city_mun, barangay, mbi_status, pso_remarks, and lgu_bgy_name) fully Editable.

Supported Geometry Types

• Polygon and MultiPolygon (Vector boundary layers)
• Point and MultiPoint (Building point layers)

Reference Layer Downstream Compatibility

The output layer ref_mbi_cases is engineered to feed directly into the MBI Validator tool. When opening MBI Validator, it will automatically detect and pre-select ref_mbi_cases as the Reference layer input.

Reviewing Boundary Precedence Decisions

Inspect 2026_province_boundary's attribute table to confirm which polygons were kept, superseded, or relabeled: a city_mun with mixed LGU/PSA submissions will show only LGU polygons for that city_mun, and any polygon whose source was blank or non-LGU will read PSA. This is the exact boundary set that Gaps/Overlaps/Disputed detection ran against.