Returns one 256×256 tile of a product in the standard XYZ Web Mercator tiling, the same scheme used by MapLibre, Leaflet and OpenStreetMap. Tiles hold data, not images. Each pixel is a 16-bit integer you decode into a physical value, and you choose the colours yourself.
Parameters
modelstringpathrequiredModel ID from /models.
productstringpathrequiredProduct name from /products. Case-sensitive.
z, x, yintegerpathrequiredTile coordinates. The path may end in .bin: …/{y}.bin.
runstringqueryRun stamp from /runs, such as 20260924T120000Z. Required unless you pass time.
hourintegerquerydefault 0Index into the model’s forecast_hour_axis. This is not the forecast hour itself; see Runs and hours.
timedatetimequeryAlternative to run and hour: a valid time in RFC 3339 format. Cyclone uses the newest run with a time step within half a step of it. Returns 418 if no run covers that time. Can’t be combined with run.
levelintegerquerydefault 0For pressure-level products, an index into the product’s levels_hpa. Ignored otherwise.
Response
The body is 131,072 bytes: 256 × 256 signed 16-bit integers in row-major order, starting at the tile’s north-west corner. The byte order is given by the product’s littleEndian flag. Responses are gzip-compressed on the wire if your client accepts it.
The encoding is also sent as headers, so you can decode a tile without calling /products first:
| Header | Example |
|---|---|
X-Data-Dtype |
int16 |
X-Data-Width, X-Data-Height |
256 |
X-Data-Scale |
0.0146484375 |
X-Data-Offset |
280 |
X-Data-Nodata |
-32768 |
Decoding
Each pixel converts to a value in the product’s units like this:
value = raw × scale + offsetPixels equal to nodata are outside the model’s domain or have no data. If a whole tile is empty, the response is 418 with the code empty_tile.
const BASE = 'https://cyclone.cssl.ca/models/rdps';
const { runs } = await (await fetch(`${BASE}/runs`)).json();
const { products } = await (await fetch(`${BASE}/products`)).json();
const { encoding } = products.find((p) => p.name === 'T2m');
const res = await fetch(`${BASE}/products/T2m/data/6/17/23?run=${runs[0]}&hour=6`);
if (res.status === 418) throw new Error('No data for this tile');
const view = new DataView(await res.arrayBuffer());
// Decode to physical values; NaN where there's no data.
const values = new Float32Array(encoding.width * encoding.height);
for (let i = 0; i < values.length; i++) {
const raw = view.getInt16(i * 2, encoding.littleEndian);
values[i] = raw === encoding.nodata ? NaN : raw * encoding.scale + encoding.offset;
}import numpy as np
import requests
BASE = "https://cyclone.cssl.ca/models/rdps"
run = requests.get(f"{BASE}/runs").json()["runs"][0]
products = requests.get(f"{BASE}/products").json()["products"]
enc = next(p["encoding"] for p in products if p["name"] == "T2m")
res = requests.get(f"{BASE}/products/T2m/data/6/17/23", params={"run": run, "hour": 6})
res.raise_for_status()
dtype = "<i2" if enc["littleEndian"] else ">i2"
raw = np.frombuffer(res.content, dtype=dtype).reshape(enc["height"], enc["width"])
values = np.where(raw == enc["nodata"], np.nan, raw * enc["scale"] + enc["offset"])How tiles are built
Cyclone stores each model on its native grid and reprojects to Web Mercator for every request. At high zoom levels each pixel takes the nearest grid cell’s value. When a pixel covers many grid cells, it takes their average, ignoring cells with no data.
Tiles for a given run, hour and level never change, and they’re served with Cache-Control: immutable. A browser or CDN cache in front of Cyclone will absorb repeat requests when users scrub back and forth in time.