Here we provide detailed descriptions of the following feeds:

• The regional extremes observations capabilities feed
• The regional extremes observations data feed

Regional extremes observations capabilities feed

Description of data feed

The regional extremes observation capabilities web service indicates when the regional extremes observations data feed was last updated, and the period it covers.

Accessing the feed via its web service

Description of web service

The capabilities web service returns the output of the capabilities data feed in either XML or JSON format. It is recommended that you query the capabilities web service to check whether the forecasts have been updated when querying for new data from the regional extremes observations web service rather than calling the regional extremes observations web service repeatedly, as this reduces the amount of data that has to be transferred, enhancing the user experience.

Possible use cases for this web service with example URLs

Whenever this web service is used the data category field in the URL should be set to txt, the resource category field should be set to wxobs, indicating that the capabilities web service concerns observation data, and, as is the case for all web services, you should also set the data format in the URL to specify whether the web service should return XML or JSON, and include your API key in the query string.

1. You would like to know which timesteps are available for the regional extremes observations data feed in XML format. In this case you would set the data category to txt, the resource category to wxobs, and the data type to xml:
   
   Example: to obtain capabilities for the regional extremes observations data feed in XML format:
   
   http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/xml/capabilities?key=<APIkey>
   
   The above example would return a file of approximately 1 kB in size
2. You would like to know which timesteps are available for the regional extremes observations data feed in JSON format In this case you would set the data category to txt, the resource category to wxobs, and the data type to json:
   
   Example: to obtain capabilities for the regional extremes observations data feed in JSON format:
   
   http://datapoint.metoffice.gov.ukpublic/data/txt/wxobs/ukextremes/json/capabilities?key=<APIkey>
   
   The above example would return a file of approximately 1 kB in size

Example of XML and JSON responses

The following examples show a typical result of a call to the capabilities web service requesting a complete list of timesteps available from the regional extremes observations web service for a given site ID.

XML

The XML that follows is a representative response to a call to the following URL, with a valid key:

http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/xml/capabilities?key=<APIkey>

JSON

The JSON that follows shows the structure of a representative response to a call to the following URL, with a valid key:

http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/json/capabilities?key=<APIkey>

Anatomy of responses

The XML and JSON responses produced by this web service are identical in terms of their high level structure and the information they represent. Each contains a single UkExtremes object (or node in XML), defined as follows:

UkExtremes

A UkExtremes object defines the capabilities for the regional extremes observations data feeds, and contains the following elements:

• extremeDate: This describes the date of the observation
• issuedAt: This describes the date at which the observation was issued, in ISO8601 format

Regional extremes observations data feed

Accessing the feed via its web service

Description of web service

This provides access to the observed extremes of weather across the UK for the day of issue. The data provided by the web service is updated on a daily basis.

Possible use cases for this web service with example URLs

Since this web service supplies observation data, whenever this web service is used the resource category field in the URL should be set to wxobs. You should also set the data format in the URL to specify whether the web service should return XML or JSON, and include your API key in the query string.

1. You would like the observed extremes of weather across the UK in XML format.
   
   Example: to obtain forecasts for a specified location at all available times in XML format:
   
   http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/xml/latest?key=<APIkey>
   
   The above example would return a file of approximately 9 kB in size
2. You would like the observed extremes of weather across the UK in JSON format.
   
   Example: to obtain forecasts for a specified location at all available times in JSON format:
   
   http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/json/latest?key=<APIkey>
   
   The above example would return a file of approximately 9 kB in size

Example of XML and JSON responses

The following examples show a typical result of a call to the regional extremes observations web service requesting the observed extremes of weather across the UK. The following section provides a detailed description of the structure and content of the responses.

XML

The XML that follows is a representative response to a call to the following URL, with a valid key:

http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/xml/latest?key=<APIkey>

JSON

The JSON that follows shows the structure of a representative response to a call to the following URL, with a valid key:

http://datapoint.metoffice.gov.uk/public/data/txt/wxobs/ukextremes/json/latest?key=<APIkey>

Anatomy of responses

The XML and JSON responses produced by this web service are identical in terms of their high level structure and the information they represent. Each contains a single UkExtremes object (or node in XML), defined as follows:

UkExtremes

The UkExtremes object comprises contains the following attributes:

• extremeDate: This describes the date of the observation
• in page HL to anchor: This describes the date at which the observation was issued, in ISO8601 format

It also contains a single Regions element.

Regions

The Regions object comprises contains a number of Region elements.

Region

Each Region object comprises contains the following attributes:

id: This gives the short name of the region

name: This gives the full name of the region

It also contains a single Extremes element.

Extremes

Each Extremes object comprises contains a number of Extreme elements.

Extreme

The Extreme object comprises contains the following attributes:

locId: This gives the location ID of the location where the extreme was observed

locationName: This gives the full name of the location where the extreme was observed

type  This gives the type of the extreme. For example 'HMAXT' would represent the highest maximum temperature, and 'LMINT' would represent the lowest minimum temperature

uom This gives the unit of measurement for the extreme

The value of the Extreme object($ in the JSON representation) gives the value of the observed extreme, in units specified in the uom attribute.