Limit results by radius around lat/lon

[RamRaider]

It appears that ALL results are returned from queries such as

//data.gov.uk/data/api/service/health/hospitals/nearest?lat=52.64105830207872&lon=1.032092571258545

which seems pointless as the returned data is much larger than it needs to be. Is there or can there be a distance limiting parameter - ie

//data.gov.uk/data/api/service/health/hospitals/nearest?lat=52.64105830207872&lon=1.032092571258545&radius=20

etc??

In the API documentation it states there is the ability to query the database directly by crafting the sql and appending to the endpoint url - but it is unclear how one would use this approach to achieve the desired distance limit mentioned.

[rossjones]

Yes, limiting and radius and paging are all things that need doing. There's no support for radius at present, although theoretically it's just a case of using ST_Distance_Sphere in this case it's a little more complicated.

In the meantime, so you can keep your resultsets small you could go to https://data.gov.uk/data/api/health#sql and try the following query

select * from hospitals 
order by ST_Distance(LatLong, ST_SetSRID(ST_MakePoint(52.64105830207872, 1.032092571258545), 4326))
limit 10;

If you then click download as json you should have the URL to use.
Obviously it isn't as useful as radius, but it might help you progress in the meantime.

[RamRaider]

:) Brilliant - thanks for the useful response and code! I shall give the example sql a try and see how I get on with that approach