Getting Started

1. Select a city in Area of Interest or upload your own KML boundary file.

2. Choose Fixed Count (you decide how many sensors) or Auto Optimize (the app decides).

3. Click ▶ Compute Optimal Placement.

4. Switch to the Results tab to see sensor positions and download them.

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Placement Mode

Fixed Count — type how many sensors you need. The algorithm spreads them as evenly as possible, biased toward high-risk areas.

Auto Optimize — set a minimum spacing (how close sensors can be) and a max cap. The app finds the optimal number automatically.

Algorithm Weights

Elevation — how much terrain height changes matter. High mountains or valleys score higher.

Building Height — how much tall buildings obstruct gas spread. Dense high-rises score higher. Real footprints and heights are automatically fetched from OSM; synthetic data is used as fallback.

Road Proximity — how close to busy roads sensors should be. Motorways score highest.

Grid Resolution

Controls how finely the area is divided. Higher = more precise but slower. 50 is good for most cities; use 80–100 for large or complex areas.

Map Layers (Layers tab)

Toggle each layer on/off independently. Switch the Base Map Style to Satellite for real-world context.

Coverage Circles show the estimated monitoring area of each sensor — adjust the radius under the toggle.

Resize Study Area

After loading a city, click Edit Area on Map. Drag the cyan corner handles or purple edge handles to resize. Click Apply & Recompute to re-run with the new area.

Exporting Results

In the Results tab, export results as CSV (sensor coordinates spreadsheet), KML (full map) (all layers, risk grid, buildings, roads and metadata for Google Earth / GIS), or JSON (GeoJSON for developers).

Coverage Radius

Risk score combines elevation variability, building density & height, and road proximity.

OSM data is cached between sessions: roads & industrial sites in localStorage, building footprints in IndexedDB (no size limit). All data is reused automatically until it expires.

Layer Cached Size Action Roads — — ↺ Refresh Buildings — — ↺ Refresh Industry — — ↺ Refresh