DENR CAR logo Republic of the Philippines GeoStratum Documentation Cordillera Administrative Region
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GeoStratum User Manual

A comprehensive guide to interactive GIS mapping, layer configurations, spatial queries, and system limitations.

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Introduction and Overview

Welcome to the GeoStratum system manual. GeoStratum is an interactive, browser-based geographic information system (GIS) designed specifically for the Department of Environment and Natural Resources - Cordillera Administrative Region (DENR-CAR).

The application consolidates land cover, land classification, biophysical profiles, hazard susceptibility, and cadastral boundaries across the six Cordillera provinces (Abra, Apayao, Benguet, Ifugao, Kalinga, and Mountain Province). It provides land-use planners, research teams, and environmental managers with access to overlapping spatial analysis metrics on the fly.

GeoStratum full map interface overview showing the Cordillera Administrative Region
Full map interface showing the Cordillera Administrative Region with active boundary layers.

Objective

To eliminate data silos by combining national agency data sets (NAMRIA) and local land records into a single, cohesive spatial interface with client-side analytical calculations.

Dual-Source Directory

Compare official national data repository layers side-by-side with local cadastral boundary maps.

Spatial Intersections

Generate instant intersection charts showing overlapping classifications and hazard risk indices.

Secured Cloud Sync

Upload custom layers securely. Registered profiles synchronize geo-assets directly with the database.

Quick Start Guide

Getting started with GeoStratum is simple. The system runs fully inside modern browsers, requiring no external GIS plug-ins. Follow these quick steps to explore the region:

  1. Navigate the Map: Left-click and drag the map surface to pan. Use your mouse scroll wheel or the zoom buttons (+/-) on the map interface to adjust the view level.
  2. Change the Basemap: Hover or click on the basemap switcher tab in the top-right corner. You can select between Satellite (imagery), Hybrid (labels and imagery), Open Street (standard road maps), or Topography (elevation contours).
  3. Locate Controls: Click the gear icon floating button in the bottom-middle of the screen to reveal the central Layers Control Dock.
  4. Inspect a Feature: Click on any provincial boundary, municipal shape, or hazard zone to select it. The Feature Details Panel will slide out in the top-left showing metadata and statistical computations.
Zoom navigation controls and map controls trigger button
Zoom controls (top-left) and the floating gear trigger (bottom-center) to open the map controls dock.
Manual button and basemap switcher at the top-right of the map
The Manual button and Basemap Switcher are located together in the top-right corner of the map.

Pro Tip

Double-clicking on any boundary zoom-fits the screen viewport automatically to that specific feature bounds.

Managing Map Layers

GeoStratum groups geospatial layers into two principal categories accessible via the switcher tabs at the top of the Map Controls panel:

  • NAMRIA Layers: Official national environmental datasets, including Land Classification (forestland vs. alienable and disposable land), Biophysical Profiles (slopes, soil erosion), and Hazard Vulnerabilities (fire, landslide, flood susceptibility).
  • Cadastre Layers: Localized municipal parcel boundaries and tenure files (e.g. National Greening Program regions, Tenurial Instruments).
Layer control panels showing NAMRIA and Cadastre tabs
Layer control panels with the NAMRIA and Cadastre panel switcher tabs at the top.
Single layer control row showing checkbox, color picker, opacity, and weight controls
A single layer row showing the visibility toggle, color picker, opacity slider, and line weight control.

Inside either tab, you can manipulate individual layers using the following control knobs:

  • Checkbox: Toggles layer visibility on/off. Green checked boxes indicate active layers.
  • Color Picker: Click the color circle to pick a custom rendering hue for the layer's polygons.
  • Opacity Slider: Slide left or right to change transparency levels (from 0% invisible to 100% solid color).
  • Line Weight: Enter or click numbers to change the outline pixel thickness for layer boundaries.
Map view with multiple active layers rendered simultaneously
Map view showing multiple active layers overlaid simultaneously across the Cordillera region.
Map view with CAD municipality boundary layer active
Municipal boundary layer rendered across the region, revealing detailed local administrative boundaries.

Layer Rendering Rationale

Modifying colors and opacities is computed immediately on active client-side vector geometries. It does not re-fetch datasets from the server, keeping interactions fluid.

Overlapping Spatial Queries

When you click any polygon on the map (for example, a municipal boundary in Abra), GeoStratum runs a real-time intersection query.

The system takes the clicked polygon geometry, cross-references it with all other currently active layers, and calculates the overlapping area.

How to analyze overlapping area:

  1. Enable the layers you want to inspect (e.g., check both CAD Municipalities and Landslide Susceptibility).
  2. Click on the municipality of interest on the map.
  3. Look at the Feature Details Panel on the left.
  4. Under the section "Area by overlapping layer", you will see a percentage-based breakdown and area values in hectares (ha) for each risk tier (Low, Moderate, High, Severe) within that municipality's borders.
Feature Details Panel showing attribute data for a selected boundary
The Feature Details Panel showing region attributes and computed area after clicking a boundary.
Feature Details Panel showing overlapping layer area breakdown chart
Overlapping layer breakdown — area percentages and hectare values per classification type within the selected boundary.

Attention

Intersection calculations are only triggered for layers that are actively turned ON. Make sure layers you want to query are checked on in the panel before selecting the boundary.

Importing Custom Datasets

GeoStratum permits researchers to bring in external geospatial vectors to overlay on top of existing Cordillera basemaps.

Supported Formats

  • GeoJSON: Single text files containing JSON spatial coordinate features (ending in .geojson or .json).
  • Zipped Shapefiles: Compressed ZIP files containing Esri shapefile files (must contain at least .shp, .dbf, and .shx files; .prj is recommended for projection matching).

Upload Workflow

  1. Open the Map Controls Panel and click on the Import tab.
  2. Click the dashed upload zone or drag-and-drop your file onto it.
  3. Wait for the import parser to process coordinates. Once successful, the layer is added to the Imported Layers list.
  4. You can assign a customized layer name, adjust outline thickness, customize color palettes, toggle layer visibility, or remove it entirely.
Import tab showing the empty file drag-and-drop upload zone
The Import tab with the upload zone ready — click or drag-and-drop your GeoJSON or zipped Shapefile here.
Import tab with a successfully uploaded custom layer in the list
After a successful upload — the custom layer appears in the list with rename, styling, and removal controls.

Account Management and Database Persistence

While guest users can upload vector layers, these layers are stored locally in the browser's temporary memory (session memory) and are discarded once the tab is closed.

To keep custom layers permanently accessible across multiple devices, users should register a free account.

Profile Sync Features:

  • Persistent Storage: Any file uploaded in the Import tab is automatically zipped and sent to the secure SQL database (geostratum_imported_layers table).
  • Device Syncing: Simply sign in on another computer to immediately load your custom vector boundaries into your map layout.
  • Secure Sign In/Out: Clicking the user profile button in the left navigation bar allows users to securely log in, register, sign out, or submit an email OTP (One-Time Password) request to recover credentials.

Screenshots and High-Fidelity Exports

GeoStratum provides a high-resolution export facility designed to easily generate map figures for inclusion in research reports or planning slide decks.

Capture Walkthrough:

  1. Click on the feature you wish to export to open the details card.
  2. Click the Camera Icon in the top-right corner of the Feature Details Panel.
  3. A preview modal appears, displaying the cropped boundary and the corresponding data tables.
  4. Select the desired file export extension:
    • PNG: Standard high-fidelity lossless format, ideal for digital documentation.
    • JPEG: Standard compressed format, best for email sharing.
    • WEBP: Modern high-compression format, optimized for web pages.
    • TIFF: Raw georeferenced-friendly image format (encoded via UTIF.js library).
  5. Click Download to save the file locally.
Camera screenshot button inside the Feature Details Panel header
The camera icon button in the Feature Details Panel header — click it to begin a screenshot capture.
Screenshot preview modal showing the captured details card and download options
The Screenshot Preview modal — choose a file format and click Download to save the capture locally.

System Limitations and Constraints

Users must understand the technical constraints of the client-side design. Here are the core limitations:

PERFORMANCE

Client-Side Rendering Overhead

GeoStratum renders layers as SVG/Canvas vectors directly in the browser window. Loading extremely large shapefiles (e.g. >10MB or containing more than 20,000 polygons) can consume significant system RAM. This may lead to browser lag, jerky panning, or browser tab crashes on lower-end devices.

CALCULATIONS

Planar (2D) Geometry Calculations

All spatial intersection calculations (such as overlap area of biophysical profiles within municipal limits) are computed via Turf.js using planar 2D geometries on the WGS84 ellipsoid. It does not adjust for the Cordillera's rugged mountain terrain elevation profiles. The calculated area may differ slightly from the true 3D surface slope area.

COORDINATES

Client-Side Projection Matching

The mapping interface operates natively in Web Mercator projection (EPSG:3857). Shapefiles in local coordinate references (e.g., PRS92 / UTM Zone 51N - EPSG:3125) are reprojected client-side using the Proj4js library. Slight shift errors (1-3 meters) may occur due to datum transformation approximations.

CAPABILITIES

No Vector Editing Capabilities

GeoStratum is primarily an analytical and visualization catalog. Users cannot split polygons, digitize new paths, edit feature attributes, or repair topological errors (like sliver polygons or boundary gaps) within the interface.

STORAGE

Guest Session Limits

If you are not logged into a verified account, custom layers are saved only in local browser session storage. If you clear cookies, open the map in an Incognito window, or refresh/close the tab, all custom configurations and uploaded datasets will be permanently lost.

Mobile Layout

GeoStratum is fully responsive and adapts its interface for smaller touchscreen devices. Below are references for how the key UI elements appear on mobile viewports.

Mobile view of the GeoStratum map interface
Mobile map view — the basemap dropdown and controls condense to icon-only buttons for a clean small-screen layout.
Mobile view of the layer control panels
Mobile layer control panels — the panel dock spans full-width at the bottom of the screen for easy touch access.
Mobile view of the Feature Details Panel
The Feature Details Panel on mobile — it slides in from the side and uses a full-width layout for readability.

Troubleshooting FAQ

Below are answers to common questions and issues that may occur while using the application:

Ensure that your Shapefile is compressed in a standard .zip file. The zip archive MUST contain the main files: .shp (geometry), .dbf (database attributes), and .shx (index). Files must not be nested inside folders within the ZIP file. Also, verify that the Shapefile isn't corrupted and has valid geometry vertices.
Sluggish performance is usually caused by having too many high-resolution layers enabled simultaneously. Open the map controls panel and uncheck layers that you do not immediately need. Try using the Satellite or Open Street basemaps instead of Hybrid, and close other browser tabs to free up RAM.
First, check your Spam/Junk email folder. The OTP email is dispatched from the server via PHPMailer; check with your local IT department to ensure outgoing server connections are not blocked by firewall rules. If using a local development server (e.g. XAMPP on localhost), verify that the mail server configuration in server/core/mail.php is configured with valid SMTP credentials.
This happens if the active layer does not fully cover the boundary region of the clicked municipal shape. The overlapping engine only displays intersection results where native data actually exists within the target polygon.
Currently, custom layer uploads are linked strictly to the user account that uploaded them. Collaborative shared maps are not supported in the current release. To share a layer, export your shapefile/GeoJSON and email it to the other user to upload on their account.