# Technical specification

## API Reference

OS NGD API – Features technical specification provides an overview of the endpoints available, as well as the parameters that can be used with each endpoint. The technical specification is intended to be used by customers who want to integrate with the API. \
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The service offers the following endpoints:

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Landing page</strong></td><td>OS NGD API – Features landing page.</td><td><a href="technical-specification/landing-page">landing-page</a></td></tr><tr><td><strong>Conformance</strong></td><td>List the OS NGD API – Features conformance to the OGC API – Features specification.</td><td><a href="technical-specification/conformance">conformance</a></td></tr><tr><td><strong>Collections</strong></td><td>Get a list of all the available OS NGD feature types.</td><td><a href="technical-specification/collections">collections</a></td></tr><tr><td><strong>Collection</strong></td><td>Get information about a specific OS NGD feature type.</td><td><a href="technical-specification/collection">collection</a></td></tr><tr><td><strong>Schema</strong></td><td>Get the schema for a specific OS NGD feature type.</td><td><a href="technical-specification/schema">schema</a></td></tr><tr><td><strong>Queryables</strong></td><td>Get a list of queryable attributes for a specific OS NGD feature type.</td><td><a href="technical-specification/queryables">queryables</a></td></tr><tr><td><strong>Features</strong></td><td>Get features in an OS NGD feature type.</td><td><a href="technical-specification/features">features</a></td></tr><tr><td><strong>Feature</strong></td><td>Get a specific feature in an OS NGD feature type by its OSID.</td><td><a href="technical-specification/feature">feature</a></td></tr></tbody></table>

## Use of CQL operators

The OS NGD API – Features supports a generic filter grammar called Common Query Language (CQL) for specifying enhanced filter criteria to return a subset of features. CQL is written using a familiar text-based syntax, making it more readable and better-suited for creating complex filters.

The following table documents the supported operators:

<table><thead><tr><th width="186">Operator Type</th><th>Supported Operators</th></tr></thead><tbody><tr><td>Comparison</td><td><code>EQUAL TO [ = ]</code>, <code>LESS THAN [ &#x3C; ]</code>, <code>LESS THAN OR EQUAL TO [ &#x3C;= ]</code>, <code>GREATER THAN [ > ]</code>, <code>GREATER THAN OR EQUAL TO [ >= ]</code>, <code>ISNULL</code>, <code>LIKE</code>, <code>IN</code>, <code>BETWEEN</code></td></tr><tr><td>Logical</td><td><code>AND</code>, <code>OR</code>, <code>NOT [ &#x3C;> ]</code></td></tr><tr><td>Array</td><td><code>AEQUALS</code>, <code>ACONTAINS</code>, <code>ACONTAINEDBY</code>, <code>AOVERLAPS</code></td></tr><tr><td>Spatial</td><td><code>INTERSECTS</code></td></tr></tbody></table>