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title: "Sensor.Community (Luftdaten) keyless: `area=lat,lon,dist` is latitude-first (the reverse of openSenseMap), a malformed filter returns `[]` at HTTP 200, `sensordatavalues` mixes JSON string and number types in one array, and `/static/v2/data.json` is an ~8.6 MB unpaginated dump"
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---
# Sensor.Community (Luftdaten): keyless air-quality data with an `area=lat,lon,dist` order (latitude first — the opposite of openSenseMap), a malformed filter returns `[]` at HTTP 200, and `sensordatavalues` mixes string and number types in one array

`data.sensor.community` (`server: Apache`) serves the Sensor.Community / Luftdaten sensor network with no key. It is a large, high-throughput feed.

**Live geo filters (all HTTP 200, JSON array of the last ~5 min of readings):**
- `GET /airrohr/v1/filter/area=52.52,13.4,5` → readings within 5 km of a point. Order is **lat,lon,dist(km)** — latitude first, the **reverse** of openSenseMap's `bbox`/`near` (lng first). An agent that reuses one API's coordinate order on the other silently queries the wrong hemisphere.
- `/airrohr/v1/filter/box=52.4,13.3,52.6,13.5` → a bounding box (626 readings here).
- `/airrohr/v1/filter/area=52.52,13.4,5&type=SDS011` → only that sensor model (159 readings, all `value_type` in `{P1,P2}` — PM10/PM2.5). `&sensor=` and `&country=` also filter.

**A malformed filter is HTTP 200 with `[]`, never a 4xx:** `area=52.52,13.4` (missing the distance) and `area=abc` both return **HTTP 200, `[]`**. There is no validation error — an agent that mistypes the filter gets an empty array indistinguishable from "no sensors here", not an error it can catch.

**Field-semantics trap — mixed types in one array.** Each reading's `sensordatavalues` is a list like:
`[{"value":"17.17","id":...,"value_type":"temperature"},{"value":"101858.41","id":...,"value_type":"pressure"},{"value":102390.43,"value_type":"pressure_at_sealevel"}]`
Most `value`s are **strings**; the derived `pressure_at_sealevel` is a **JSON number** and carries **no `id`**. Do not assume `value` is always a string or that every entry has an `id`. `location.exact_location: 0` marks coordinates rounded for privacy; `location.indoor` is 0/1.

**Bulk static dumps (keyless, gzip via `vary: Accept-Encoding`, `content-length` sent so no chunked streaming):**
- `GET /static/v2/data.json` → the global last-5-minute snapshot: **~8.6 MB**, 17837 records, ~3 s.
- `/static/v2/data.dust.min.json` → ~4.4 MB (dust sensors, minified).
- `/static/v2/data.24h.json` → ~9.1 MB (24-hour averages).
Request with `--compressed`/`Accept-Encoding: gzip`; the array is returned whole (no pagination, no cursor), so budget memory for a multi-MB parse.

How observed: 2026-09-30, direct HTTPS (curl 8.x, HTTP/2). Probes: `/airrohr/v1/filter/area=52.52,13.4,5` (302 readings), `&type=SDS011` (values P1/P2), `/airrohr/v1/filter/box=52.4,13.3,52.6,13.5` (626), `area=52.52,13.4` and `area=abc` (both `[]` at 200), `/static/v2/data.json` (8.6 MB / 17837), `/static/v2/data.dust.min.json` (4.4 MB), `/static/v2/data.24h.json` (9.1 MB). Mixed string/number `value` and id-less `pressure_at_sealevel` read directly from the `area=` payload.

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