Getting Started
What is GEMMA?
GEMMA stands for GIS Extension for Map Management and Analysis. It is a QGIS processing plugin developed by the Geospatial Management Division (GMD) of the Philippine Statistics Authority (PSA).
The plugin provides a comprehensive suite of GIS tools for official boundary management, topology checking, geometry repair, PSGC metadata standardization, enumeration area delineation, and mobile field data collection packaging.
Requirements
| Requirement | Minimum Version | Recommended Version |
|---|---|---|
| QGIS | 3.0 or later | QGIS 3.40 LTR |
| Python | 3.x (bundled with QGIS) | Python 3.9+ |
| OS | Windows, macOS, or Linux | Windows 10/11 |
Installation
Method 1: QGIS Plugin Repository (Recommended)
Installing via custom repository allows QGIS to automatically detect and notify you of plugin updates:
- Open QGIS.
- Go to Plugins → Manage and Install Plugins.
- Select the Settings tab.
- Click Add… to add a repository.
- Set Name to
GEMMA Repositoryand URL to:https://gemma-plugin.vercel.app/gemma.xml - Click OK, then click Reload All Repositories.
- Go to the All tab, search for GEMMA, and click Install Plugin.
Method 2: Install from ZIP
- Download the latest release from the GitHub Releases page.
- Open QGIS.
- Go to Plugins → Manage and Install Plugins.
- Select the Install from ZIP tab.
- Click Browse and select the downloaded
gemma-plugin-v*.zipfile. - Click Install Plugin.
User Interface & Menu Overview
After installation, GEMMA tools can be accessed through three interfaces in QGIS: the Gemma Menu, the Gemma Toolbar, and the Processing Toolbox.
Gemma Menu Bar
The Gemma menu is added to the top menu bar in QGIS, structured into logical submenus:
| Submenu | Action / Tool | Shortcut | Description |
|---|---|---|---|
| Updating of Boundaries | Check and Update | — | 3-Phase dialog for georeferencing navigation, error scanning/repair, and PSGC metadata updating |
| Updating of Boundaries | PSA - LGU Comparison Review | — | Opens the comparison dock panel to review matched PSA and LGU boundary layers side-by-side |
| Updating of Boundaries | Know Your Projection! | — | Coordinate diagnosis, Philippine CRS auto-detection, and 2D affine georeferencing |
| Updating of Boundaries | Package Style Loader | — | Interactive dialog to organize layer hierarchies and apply QML symbology and labeling |
| EA Delineation | EA Delineation and Merging | — | Launcher dialog for pre-processing, gap filling, delineation, and merging of enumeration areas |
| EA Delineation | Package for QField | Ctrl+Alt+Q | Offline project packaging dialog for field data collection with QField |
| Others | Geometry Repair Toolkit | — | Standalone dialog for scanning, canvas highlighting, and in-place polygon geometry repairs |
| Others | Package Layers by City/Mun | — | Split reference layers into municipal GeoPackages placed in individual city/mun folders |
Gemma Toolbar
The Gemma Toolbar provides immediate one-click access to core interactive dialog workflows:
| Icon | Tool | Access | Description |
|---|---|---|---|
 | Check and Update | Toolbar Button | Open the 3-Phase boundary management dialog |
 | EA Delineation and Merging | Toolbar Button | Open the Enumeration Area delineation launcher |
 | Package for QField | Toolbar Button | Package layers for mobile field data collection (Ctrl+Alt+Q) |
Processing Toolbox — GMD Pipeline
All batch processing algorithms are integrated into the QGIS Processing framework under the GMD Pipeline provider:
- Open the Processing Toolbox by clicking Processing → Toolbox or pressing
Ctrl+Alt+T. - Expand the GMD Pipeline provider tree to access individual processing algorithms.
Tool Directory
GEMMA tools are organized into three primary functional suites matching the documentation guides:
1Map Tools
Tools designed for LGU boundary management, 1Map data harmonization, topology auditing, and official PSGC metadata standardization:
| Tool | Access | Description |
|---|---|---|
| MBI Checker | Processing Toolbox | Detect gaps and overlaps between barangay polygon boundaries with building point validation and reference case exclusion |
| MBI Validator | Processing Toolbox | Cross-check Reference MBI layers against Checker GAP/OVERLAP layers to audit status mismatches |
| Run Analysis | Processing Toolbox | Perform boundary discrepancy detection across polygon layers and building points, generating reference MBI case layers |
| Fill Polygon Gaps | Processing Toolbox | Automatically fill gaps between polygons and assign them to neighboring barangays |
| Export Preliminary Polygons | Processing Toolbox | Merge and export resolved boundary layers into consolidated GeoPackages for 1Map submission |
| Update Metadata | Processing Toolbox | Standardize LGU boundary layers with PSGC geocodes, cascading administrative filters, and GPKG export |
| Update Metadata (by Geocode) | Processing Toolbox | Perform direct PSGC left-join on LGU boundary layers using geocodes, auto-populating 15-attribute schemas |
| Fix LGU CRS / Geometry | Processing Toolbox | Batch-correct local arbitrary grid coordinates (~0 to ~100,000) to standard WGS 84 (EPSG:4326) |
| Join Barangay Attributes | Processing Toolbox | Match vector attributes with official PSGC tables via fuzzy matching and Roman numeral normalization |
| Check and Update | Menu & Toolbar | Interactive 3-Phase dialog workflow for georeferencing, geometry error scanning/repair, and metadata updating |
| PSA - LGU Boundary Comparison | Processing Toolbox | Audit PSA reference boundaries against LGU-submitted polygons using geocodes, alignment models, and building point validation |
| Know Your Projection! | Menu & Processing Toolbox | Diagnose CRS, auto-detect Philippine candidates, and georeference local CAD grids |
| Package Layers by City/Mun | Menu & Processing Toolbox | Split reference layers into municipal GeoPackages placed in individual city/mun folders |
| Package Style Loader | Gemma Menu | Interactive dialog to organize layer hierarchies and apply QML symbology and labeling |
Geometry & Repair
Tools for validating, diagnosing, and repairing vector polygon geometry defects:
| Tool | Access | Description |
|---|---|---|
| Geometry Repair Toolkit | Gemma → Others | Standalone interactive dialog to scan, highlight on map canvas, and repair invalid geometries in-place |
| Scan Geometry Errors | Processing Toolbox | Scan vector polygon layers for specific geometry and topology defects and generate a Point Error Layer |
| Repair Polygon Geometries | Processing Toolbox | Reconstruct invalid polygon geometries and recover missing shapes into a clean vector output layer |
| Clip Project Layers by Extent | Processing Toolbox | Batch clip multiple vector layers to a target administrative polygon boundary with optional buffer |
QField & Enumeration
Tools for field data collection packaging and census Enumeration Area delineation:
| Tool | Access | Description |
|---|---|---|
| Package for QField | Menu & Toolbar (Ctrl+Alt+Q) | Package QGIS project layers for mobile offline field data collection with QField |
| EA Delineation and Merging | Menu & Toolbar | Unified module for pre-processing, gap filling, delineation (splitting), and merging of Enumeration Area boundaries |
Updating the Plugin
- Repository Install: QGIS automatically checks for updates on launch. Navigate to Plugins → Manage and Install Plugins → Upgrade All.
- ZIP Install: Download the latest ZIP and re-install via Install from ZIP to overwrite the previous version.
Changelog
For version history and detailed release notes, check our dedicated Changelog Page or visit GitHub Releases.
Support
For bug reports and feature requests, please use the GitHub Issues page.
For direct support, contact the GMD team at gmd.support@psa.gov.ph.