Tianjian Qin

What it does

NetSpectra proposes a hybrid dynamic graph for movement/trade networks: preserve farm-level resolution inside a chosen focal region, while contracting everything outside into regional supernodes and superflows. This keeps local detail where it matters, without losing a coherent national context.

• TEA / TNA — temporal appearance of edges/nodes (new/reactivated/persistent/churn).
• π‑mass — where a random walk “spends time” (Farm vs Region mass on the LIC).
• Magnetic Laplacian spectra — directed spectral signatures that keep flow directionality.

For formal definitions and interpretation guidelines, see the blog post.

Quickstart

The simulator is a static HTML app (D3 + Web Worker). Run it from a local server so browser fetch calls work.

Ensure the GeoJSON files are available at the expected paths (or edit the fetch paths in the simulator): nl_corop.geojson and nl_corop_labelpoint.geojson.

How to use

1. Select a focal region and choose the number of farms to simulate (≤ 100).
2. Tune dynamics: p_keep for persistence and birth probabilities for new edges.
3. Use the Day slider to step through the 10-day discrete-time network.
4. Toggle Unweighted / Weighted to decide whether π‑mass and spectra use edge weights.
5. Use Spectrum quality (Fast / Balanced / Full) to trade speed for fidelity.

The bottom-left status badge in the map panel shows build progress; hover it to reveal a cancel action.

Embedding

NetSpectra is designed to embed cleanly in articles and documentation. It supports:

• Automatic iframe height resizing via iframe-resizer.
• Dark-mode synchronization with a site-level #darkmode checkbox (if present).

See the example usage in: the blog post.

Roadmap

• Faster directed spectral solvers (top‑k eigensolvers / WASM backends).
• Additional higher‑order temporal statistics and diagnostics.
• Drop-in support for other regional maps and projections.
• Weighted TEA/TNA variants for high-frequency movement systems.