SCOPE

Sensor Coverage Optimisation and Placement Engine

A web-based tool for evaluating and optimizing sensor placement for atmospheric detection. This repository contains the SCOPE detection model, interactive UI, and reference documentation.

Getting Started

Prerequisites

• A modern web browser (Chrome, Firefox, Safari, Edge)
• Optional: Node.js for running the model directly

Using the Web Tool

1. Clone the repository:

   git clone https://github.com/tmcascs/SCOPE.git
   cd SCOPE

2. Open the tool:

   • Simply open index.html in your browser
   • No build or installation required

3. Enable Google Maps (optional):

   • The tool defaults to Esri World basemap
   • To use Google Maps, add your API key:
     • Open index.html in a text editor
     • Find the line: key=YOUR_GOOGLE_MAPS_API_KEY
     • Replace with your actual Google Maps API key
     • Save and reload in browser

Using the Tool

Main Workflow

1. Define sources: Click "Add Source" to place emission sources on the map
2. Configure sensors: Use "Add 0.3ppm Sensor" or define custom sensors with different detection limits
3. View coverage: Color-coded source markers show detection coverage for each source — the percent of hours emissions are expected to be detected (red = poor, orange = fair, green = good)
4. Optimize placement: Drag sensors to improve coverage; view overall coverage score updates in real time
5. Export results: Save siting as JSON, upload previous sitings, or export PDF reports

Map Controls

Element	Purpose
Site Name	Custom label for your analysis site
Go to Location	Pan map to a specific latitude/longitude
Upload Siting	Load a previously saved sensor/source configuration
Save Siting	Export current layout as JSON file
Export PDF	Generate printable PDF with map, wind rose, and statistics
Basemap Select	Choose between Esri World (default) or Google Maps

Display Checkboxes

Checkbox	Effect
Color sources by coverage	Color-code sources by detection coverage percentage (percent of hours emissions expected to be detected)
Show sensor discs	Display detection range circles (blue: 0.3ppm sensors)
Show custom discs	Display detection range circles for custom sensors
Minimize sources	Collapse source list for cleaner map view

Sensor Controls

Standard 0.3ppm Sensor

• Built-in sensor type with fixed 0.3 ppm detection limit
• Shows range circle in blue when "Show sensor discs" is checked

Custom Sensors (Slots 1 & 2)

• Define custom detection limits (MDL in ppm)
• Click "+ Define Sensor" to configure
• Set detection limit, then click Add to place on map
• Click ✕ to remove

Wind Rose & Detection Timing

Control	Purpose
Fetch (ERA5)	Download historical wind data (date range is optional; defaults to recent period)
Start / End dates	Set time range for ERA5 wind data fetch (appears only after fetching)
Wind rose visualization	Polar histogram showing wind direction frequency and speed distribution
Emission rate selector	Choose emission rate (1–100 kg/h) for detection model input
Recompute detection timing	Calculate Time-To-Detection (TTD) statistics based on wind data and sensor placement

Detection Timing Results

Metric	Meaning
Mean TTD	Average hours until detection across all sources and wind conditions
P50 TTD	Median (50th percentile) detection time
P90 TTD	90th percentile detection time (worst case typical scenario)
Sources not detected	Percentage of source/wind combinations that never reach detection range
Coverage Score	Percent of hours expected to detect emissions across all sources — overall siting quality based on detection reliability and frequency

Coordinate Tables

Sources Table

• Lists all emission sources with:
  • Name & Label: User-defined identifier
  • Height (m/ft): Source height above ground (toggleable units)
  • Cov%: Detection coverage — percent of hours emissions from this source are expected to be detected
  • P50 TTD: Median time-to-detection for this source
  • P90 TTD: 90th percentile time-to-detection
  • Nearest Sensor: Distance to closest sensor

Sensors Table

• Lists all sensors with:
  • Type: Standard (0.3ppm) or custom detection limit
  • MDL (ppm): Minimum detection limit
  • Lat / Lon: Sensor coordinates

Interaction Tips

• Click on map to place sources or sensors
• Drag to reposition any marker
• Double-click a marker to delete it
• Enable "Auto-recompute on drag" for live coverage updates while dragging (disable on large sites for smoother performance)
• Check wind data status badge (green ✓ = active data, yellow ⚠ = stale, gray = none) to see data freshness

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Detection Model

SCOPE uses a Gaussian plume model to compute atmospheric dispersion and detection ranges based on:

• Emission rate (kg/h): source strength
• Detection limit (ppm): sensor sensitivity
• Height difference (m): vertical separation between source and sensor
• Wind speed (m/s): atmospheric mixing conditions

Model Inputs & Outputs

Inputs:

• Emission rate in kg/h
• Concentration detection limit in ppm
• Source-to-sensor height difference in meters (0 to 20m)
• Wind speed in m/s

Outputs:

• maxRangeM: Outer detection radius (downwind maximum range)
• minRangeM: Inner crossing radius (upwind minimum range where concentration exceeds limit)
• limitHit: Flag indicating if model reached computational horizon

Understanding Detection Limits

Common detection limits:

• 0.3 ppm: Standard environmental monitoring threshold
• 1.0 ppm: Regulatory reporting levels (varies by jurisdiction)
• 10.0 ppm: Industrial safety levels

Higher detection limits = shorter detection ranges; lower limits = longer ranges.

Reviewing the Model

See references/Gaussian Plume Model for SCOPE tool.pdf for:

• Mathematical formulation of the plume model
• Input parameter ranges and assumptions
• Validation against field data
• Model limitations and applicability

Programmatic Access

For direct model access in Node.js:

npm install
npm run example

This queries the detection lookup table programmatically and returns:

{
  "maxRangeM": 300,
  "minRangeM": 10.628,
  "limitHit": true,
  "cappedAtM": 300
}

See examples/query-example.mjs for implementation details.

Model Files

• data/detection_lookup.json: Precomputed lookup table (emission rate, detection limit, height, wind speed)
• src/model.js: Lookup access and interpolation logic
• references/Gaussian Plume Model for SCOPE tool.pdf: Model background and validation

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Included Files

• index.html: Interactive web-based siting tool
• app.js: Tool logic, map handling, coverage calculations
• styles.css: Styling and responsive layout
• scope_logo.svg: SCOPE brand logo
• data/detection_lookup.json: Detection model lookup table
• src/model.js: Model interface
• examples/query-example.mjs: Example model queries
• references/Gaussian Plume Model for SCOPE tool.pdf: Model reference

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License

This project is licensed under PolyForm Noncommercial License 1.0.0.

Commercial use is not permitted. Authorized non-commercial uses include research, education, and internal organizational analysis.