---
title: "Exhaustive observability survey for a sensor"
method: GET
path: "/api/v1/collection/observability"
---

# Exhaustive observability survey for a sensor

`GET /api/v1/collection/observability`

## Request

- Base URL: `https://offnadir-delta.com`
- URL: `https://offnadir-delta.com/api/v1/collection/observability`
- Auth: one of:
  - HTTP bearer
  - API key in header `X-API-Key`

Costs 1 token(s) per request. Evaluates EVERY event in the window against a sensor's resolving power using each event's precomputed required resolution, and returns observable vs not counts, the breakdown by required resolution, and the top observable events with their imaging rationale. Observability is resolvability — whether the physical mark is large enough: sentinel-2 is ~10 m optical (needs daylight and clear sky), sentinel-1 is SAR (all-weather, day or night). Deterministic; no LLM and no per-event cost.

## Query parameters

- `sensor` 'sentinel-2' | 'sentinel-1'
- `bbox` string
- `start_date` string, date
- `end_date` string, date
- `categories` string
- `min_geoint_score` number
- `top_n` integer

## Response `200`

Observable vs not, with the per-resolution breakdown.

- object
  - `meta` object
  - `survey` object

## Other responses

- `400` (unresolved $ref)
- `401` (unresolved $ref)
- `402` (unresolved $ref)
- `429` (unresolved $ref)

---

[API](https://skmtc.dev/offnadir-delta/apis/off-nadir-delta-api.md) · [All operations](https://skmtc.dev/offnadir-delta/apis/off-nadir-delta-api/llms.txt) · [OpenAPI document](https://skmtc.dev/offnadir-delta/apis/off-nadir-delta-api/revisions/5cf3f2bed5a2?raw)