Please note in some of the examples below I have been having trouble with wordpress ‘correcting’ quote marks in my text. If you find the queries don’t work you may need to manually replace the copied quote marks from below with new ones via your keyboard. Hope that makes sense.
One of the biggest improvements to the new Ordnance Survey Linked Data site is the much improved search functionality. You can either search over a specific dataset (e.g. the Code-Point(R) Open linked data) or over all the combined datasets. I will first give some examples of using the Boundary-Line(TM) search API.
The Boundary-Line search API explorer can be found here. The simplest use of this search API is to enter some text for the name of an administrative area or the GSS code (the ONS identifier for a statistical region) into the search box. To get started enter Southampton into the query box. You will see that the search results are returned in JSON (RSS and Atom are additional options). Results contain the URI of the entities that match your queries along with a number of useful attributes.
Note that the Request box shows the actual GET request that is being done, and you can use this GET request in your applications. Now try searching for a GSS code, enter E06000045 into the query box. You should see results for the City of Southampton returned. So far so straight forward. The search function also allows for wildcards in search, for example in the Query box type:
It is also possible to narrow search results by type. Recall that the search for Southampton returned both Westminster constituencies and a unitary authority with Southampton in their name. To just find the Westminster constituencies search for the following:
label:Southampton AND type:”http://data.ordnancesurvey.co.uk/ontology/admingeo/WestminsterConstituency“
The search API also allows you to perform a number of simple spatial queries. The first of these are bounding box queries. For the Boundary-Line data you can specify a bounding box, and find all the administrative regions whose centroids lie within that bounding box. The bounding box can be expressed in eastings and northings. For example try the following:
easting:[371000 TO 374000] AND northing:[161000 TO 164500]
in the query box.
The answers can be narrowed down further by specifying the type of object that should be returned. For example to just get the civil parishes in this bounding box try the following:
easting:[371000 TO 374000] AND northing:[161000 TO 164500] AND type:”http://data.ordnancesurvey.co.uk/ontology/admingeo/CivilParish“
Another type of simple spatial query we can do in the search API is ‘find me all feature of a kind type within a certain radius of a given point’. Here the point can be specified in either lat/long or easting/northing. To find all of the civil parishes in a 50 km radius of the point with easting 442339 and northing 112882 put:
into the query box and put the appropriate values in the easting and northing boxes, followed by a 50 in the radio search box. If, for example, you want to perform this query again but find civil parishes and districts enter the following into the query box:
type:”http://data.ordnancesurvey.co.uk/ontology/admingeo/CivilParish“ OR type:”http://data.ordnancesurvey.co.uk/ontology/admingeo/District“
and try the query again.
These are just some simple examples of the search API. The full documentation is here.