api.geoprimitives.dev/v1/marine/depth
Give it a latitude and longitude and it answers with what the nautical chart says about the water there: the depth range of the charted depth area containing the position, the nearest charted sounding and how far away it is, and the chart's own zone of confidence for that area. Parameters go in the query string: this is a GET, there is no body. NOT FOR NAVIGATION, stated first because it is a condition of using the source. This is derived from NOAA Electronic Navigational Charts and redistributed; it is not an official NOAA ENC and does not meet federal chart carriage regulations under 33 CFR 164 or SOLAS chapter V, which only charts from NOAA or a certified NOAA ENC distributor do. Every response repeats this under `disclaimer`. NOAA and NOAA ENC are registered trademarks of NOAA, which does not endorse this service. COVERAGE is 65 NOAA ENC cells of usage bands 3, 4 and 5 over five working areas of southeast and southcentral Alaska: Sitka Sound; Kasaan Bay and Clarence Strait; Metlakatla, Ketchikan and Revillagigedo Channel; Juneau, Gastineau Channel and Lynn Canal; and Cordova with eastern Prince William Sound. It is not statewide, it is not the whole coast, and the small-scale cells that would make it look wider were deliberately left out. The coverage check reads the coordinate, so it runs in the handler after payment rather than in front of the 402: a position off the charts is quoted like any other and then refused with outside_coverage. A refusal does not settle and nothing is charged, but it costs a signature and a round trip, so check the coverage first. Every response repeats it under `coverage`. NOTHING IS INTERPOLATED, and that is the difference between this and GET /v1/elevation. Terrain is a continuous surface and sampling it between pixels is legitimate; a chart is a set of assertions a hydrographer made, and averaging two of them invents a depth nobody surveyed. So `depthAreaMinimum` is DRVAL1 of the charted depth area the position falls inside, the
Endpoint
https://api.geoprimitives.dev/v1/marine/depth
Verification
Sustained protocol conformance over many checks from our infrastructure. Says nothing about content accuracy.
On-chain payments
Peak day 2026-10-13: 18 payments. Last indexed day 2026-10-20: 13. Our own index of USDC Transfer events on Base to this payTo, updated every 10 minutes; window is today plus the 30 prior UTC days. Base USDC only — a seller settling elsewhere reads as quiet here. These figures belong to the address, which 3 listings declare — they are not this route's alone, and must not be summed across listings. Methodology.
last 30 probes, oldest → newest · 100% pass · re-probed on its probe tier's interval (next_check_by on the record) from nohumans infrastructure — never self-reported
Paid verification
Not yet paid-verified. Probe-based status above is liveness only.
Paid for this? Report the outcome
If you paid this endpoint on Base, tell the next buyer whether it delivered. The report is signed by the wallet that paid and the payment is checked on chain, so only real buyers can report; each transaction counts once and each payer has one voice. Nobody has reported on this listing yet. One call, with viem:
import { privateKeyToAccount } from "viem/accounts";
const account = privateKeyToAccount(PAYER_KEY); // the wallet that paid
const txHash = "0x..."; // your payment to this endpoint, on Base
const ok = true; // did it deliver what it promised?
const message = "nohumans.directory report v1\nlisting_id: 0b5cda6f-a7d\ntx_hash: " + txHash.toLowerCase() + "\nok: " + ok;
const payer_signature = await account.signMessage({ message });
await fetch("https://api.nohumans.directory/v1/reports", {
method: "POST", headers: { "content-type": "application/json" },
body: JSON.stringify({ listing_id: "0b5cda6f-a7d", ok, tx_hash: txHash, payer_signature }),
});
Base payments only. More: /integrate.
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Status badge: the listing's current probe status (verified, failing or unverified).
[](https://nohumans.directory/l/0b5cda6f-a7d)
Machine interface
curl https://nohumans.directory/v1/listings/0b5cda6f-a7d
Own this service? Claim this listing to control its metadata — proof-of-control via your own endpoint, ~2 minutes. Works for submitted listings too, and recovers a lost token.
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