This page contains detailed documentation on the surface pressure chart capabilities feed

Surface pressure chart capabilities feed

Description of data feed

The surface pressure chart synoptic analysis and forecast capabilities data feed provides information on when the current surface pressure chart were issued, and also lists the timesteps for which surface pressure are available, and the URIs of the surface pressure synoptic analysis and forecast charts themselves in gif format.

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.

Possible use cases for this web service with example URLs

Since the surface pressure chart synoptic analysis and forecast capabilities web service concerns image data, whenever this web service is used the data category field in the URL should be set to image, and the resource category field should be set to wxfcs. 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 surface pressure chart data feed in XML format. In this case you would set the data category to image, the resource category to wxfcs, and the data type to xml:
   
   Example: to obtain capabilities for the surface pressure chart data feed in XML format:
   
   http://datapoint.metoffice.gov.uk/public/data/image/wxfcs/surfacepressure/xml/capabilities?key=<APIkey>
   
   The above example would return a file of approximately 3 kB in size
2. You would like to know which timesteps are available for the three surface pressure chart data feed in JSON format. In this case you would set the data category to image, the resource category to wxfcs, and the data type to json:
   
   Example: to obtain capabilities for the surface pressure chart data feed in JSON format:
   
   http://datapoint.metoffice.gov.uk/public/data/image/wxfcs/surfacepressure/json/capabilities?key=<APIkey>
   
   The above example would return a file of approximately 3 kB in size
3. 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 surface pressure chart 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/wxfcs/regionalforecast/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/wxfcs/regionalforecast/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.

BWSurfacePressureChartList

The BWSurfacePressureChartList object comprises a number of BWSurfacePressureChart objects, defined below.

BWSurfacePressureChart

The BWSurfacePressureChart object contains the following elements:

• DataDate: This gives the Issued Date of the chart
• ValidFrom: This specifies the start of the validity period for the forecast
• ValidTo: This specifies the end of the validity period for the forecast
• ProductURI: This is the URI that will retrieve the chart
• DataDateTime: This is the time at which the chart was issued
• ForecastPeriod: This gives the number of hours after the DataDateTime of the start of the validity period of the forecast