# Cable Latency Survey

Measured round-trip times between cities, compared with the minimum
propagation time along submarine-cable routes on four models of the Earth's
surface: a sphere, a North-pole azimuthal equidistant (AE) map, an AE map
centred on 0°N 0°E ("dual-pole"), and a flat Mercator map. A round-trip time
below the fibre propagation floor along a model's route is inconsistent with
that model.

- Report: https://pingstats.aethercosmology.com (also `cable_latency_survey_report.html`, a single file that works offline)
- Code: MIT (`LICENSE`). Measurements and derived data: CC BY 4.0, with third-party terms (`LICENSE-DATA.md`).

## Files

| Path | Contents |
|---|---|
| `cable_latency_survey_data_v2.json` | **Current data hand-off.** 29,341 measurements, 305 sites, every routed path and cable geometry (`[lon, lat]`). The `revision` block lists the changes from v1. |
| `cable_latency_survey_data.json` | v1: the same measurements without coordinates. Kept for reference. |
| `cable_latency_survey_report.html` | The report, identical to the website. |
| `src/` | Pipeline code, raw logs and derived data (below). |
| `tests/` | Headless-browser checks of the report (`tests/run.sh`). |

### Raw measurements

| Source | File |
|---|---|
| Globalping probes, runs 1 and 2 | `src/data/live_20261023T1812Z.json`, `src/data/live_run2.json` (each result with its Globalping measurement ID) |
| Vultr servers (8, 2026-10-23 21:23–22:30 UTC) | `src/data/vps/<server>/ping.log`, `src/data/vps/<server>/mtr.log` (traceroutes) |
| Residential connection, Michigan | `src/data/home/ping.log` (location withheld) |
| RIPE Atlas sea crossings | `src/data/trace.json` (hops, timings, measurement and probe IDs) |
| WonderNetwork, 2020-07-19/20 | per-pair statistics `src/data/wn_clean.json`; archive downloaded by `src/fetch_raw.sh` |

## Pipeline

Run from `src/`. The measurement steps contact external services and are not
needed to rebuild the report.

| Step | Script | Output |
|---|---|---|
| Distance on each model, constants | `models.py` | — |
| Globalping measurements | `measure.py` | `data/live_*.json` |
| Vultr servers: create, measure, collect, delete | `vps.py` | `data/vps/` |
| Vultr logs to measurements | `vps_analyze.py` | `data/vps_cells.json` |
| WonderNetwork archive: statistics, mislocated servers | `analyze_wn.py` | `data/wn_clean.json` |
| Published cable lengths on each model | `cables.py` | `data/cables.json` |
| RIPE Atlas sea crossings | `trace.py` | `data/trace.json` |
| Cable-and-land routing on each model | `network.py` | `data/network.json` |
| Best attainable flat arrangements | `flatfit.py` | `data/flatfit.json` |
| Network attribution from public BGP data | `asmap.py` | `data/asmap.json`, `data/rpki.json` |
| Shape fit without positions | `pingmap.py` | `data/pingmap.json` |
| North-pole AE longitude solver (hand-off only) | `solver.py` | `data/solver.json` |
| Report | `build.py` | `site/index.html`, `web/index.html` |
| Data hand-off | `export.py` | `handoff/cable_latency_survey_data_v2.json` |

## Reproduce

```bash
git clone https://git.aethercosmology.com/toby/cable-latency-survey.git
cd cable-latency-survey/src
pip install -r requirements.txt
./fetch_raw.sh          # TeleGeography, WonderNetwork and BGP inputs (not redistributed)
python3 build.py        # the report, from the files in data/
python3 flatfit.py      # flat arrangements
python3 export.py       # the data hand-off
```

`build.py` needs only `data/` and the TeleGeography files; it does not contact
any measurement service. `fetch_raw.sh` reports whether the TeleGeography data
it downloads matches the snapshot used (`src/raw/tg.sha256`).

Browser checks: `cd tests && npm install && CH=/path/to/chromium ./run.sh`.