# Product details ## Feature types OS MasterMap Greenspace Layer contains one feature type: GreenspaceArea OS MasterMap Greenspace Layer is comprised of a subset of the *TopographicArea* polygons from OS MasterMap Topography Layer (which represent topographic objects that have a polygon-based geometry). Only polygons which have been classified as a form of green space will be supplied. This subset of polygons will have the Topographic Identifier (TOID) and version number from OS MasterMap Topography Layer (to enable the datasets to be used in conjunction) plus additional attributes providing the green space-specific information.
OS Greenspace MasterMap Layer data showing detailed polygons overlaid on OS MasterMap Topography Layer.

OS MasterMap Greenspace Layer data showing detailed polygons overlaid on OS MasterMap Topography Layer

## Attributes ### **TOID** The unique reference number of the feature in OS MasterMap Topography Layer. Combined with the version number, this enables joins with the Topography Layer dataset. ### **Version** The version number of the feature in OS MasterMap Topography Layer. This identifies the specific version of Topography Layer feature this dataset was created from. Combined with the TOID, this enables joins with the Topography Layer dataset. ### **Primary function** The main function of the green space area. Functions are determined from a specific green space list, and for features within this dataset can be found below. ### **Secondary function** Where a polygon has more than one green space function present, this field will be populated with the second function. These functions come from the same list as the Primary Functions. The order of the Primary and Secondary Functions is predetermined by a hierarchy (shown later in this guide) and does not indicate an order of importance or scale. ### **Primary form** The main form of the green space area. Forms are determined from a specific green space list. A list of the possible forms for features within this dataset can be found later in this section. ### **Secondary form** Where a polygon has more than one green space form present, this field will be populated with the second form. These forms come from the same list as the Primary Forms. The order of the Primary and Secondary Forms is predetermined by a hierarchy (shown later in this guide) and does not indicate an order of importance or scale. ## OS Open Greenspace lookup table OS Open Greenspace is part of Ordnance Survey’s Open Data portfolio and depicts the location and extent of exercise and recreation facilities likely to be open to the public. This Open Data product was designed alongside OS MasterMap Greenspace Layer, and it is intended that the two products can be used together easily. A lookup table exists to form a link between the two products and is provided in the full Great Britain (GB) supply of OS MasterMap Greenspace Layer. Further information can be found in the[ technical specification](/os-downloads/~/changes/AJZwzCsyrD9hiTbOxIbO/topography/os-mastermap-greenspace-layer/os-mastermap-greenspace-layer-technical-specification.md). --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.os.uk/os-downloads/~/changes/AJZwzCsyrD9hiTbOxIbO/topography/os-mastermap-greenspace-layer/os-mastermap-greenspace-layer-overview/product-details.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.