---
title: "GET /udl/radarobservation/history/count"
method: GET
path: "/udl/radarobservation/history/count"
tags: ["Observation"]
---

# GET /udl/radarobservation/history/count

`GET /udl/radarobservation/history/count`

## Request

- Base URL: `https://unifieddatalibrary.com`
- URL: `https://unifieddatalibrary.com/udl/radarobservation/history/count`
- Auth: none declared

Service operation to return the count of records satisfying the specified query parameters. This operation is useful to determine how many records pass a particular query criteria without retrieving large amounts of data. See the queryhelp operation (`/udl/<datatype>/queryhelp`) for more details on valid/required query parameter information.

## Query parameters

- `obTime` string, date-time, required
- `firstResult` integer
- `maxResults` integer

## Response `200`

OK

## Other responses

- `400`: Bad Request
- `401`: Invalid/Missing User Credentials
- `403`: User Is Not Authorized
- `405`: Method Not Allowed
- `406`: MediaType Not Accepted by Request Headers
- `429`: Rate of Requests Exceeds Allowed Limit
- `500`: Internal Server Error

## Changes

> 12 revisions in range; 1 could not be searched.

- **2025-05-29** `4e1cbc17e814`: 2 info
  - added the new optional `query` request parameter `firstResult`
  - added the new optional `query` request parameter `maxResults`
- **2025-04-16** `75f764c843a9`: 2 info
  - api operation id `countHistory_50` removed and replaced with ``
  - the endpoint scheme security `BasicAuth` was removed from the API

[Operation history](https://skmtc.dev/bluestaq/apis/unified-data-library-services-api/changes/udl/radarobservation/history/count/get.md)

---

[API](https://skmtc.dev/bluestaq/apis/unified-data-library-services-api.md) - [All operations](https://skmtc.dev/bluestaq/apis/unified-data-library-services-api/llms.txt) - [OpenAPI document](https://skmtc.dev/bluestaq/apis/unified-data-library-services-api/revisions/bd17bc53681e?raw)