> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/maps-and-imagery-portfolio/os-mastermap-topography-layer/os-mastermap-topography-layer-technical-specification/product-themes/structures.md).

# Structures

Structures are defined as features that are man-made constructions but do not qualify as buildings

(for example, Band Stands and Clock Towers). These features may or may not obstruct passage at ground level. OS MasterMap Topography Layer contains information relating to all permanent structures that are considered large enough to be included. The image below gives some examples (highlighted in dark grey) of structures:

<figure><img src="/files/VhXdNfriKljzRe3GRq5d" alt="Screenshot from OS MasterMap Topography Layer near Southampton Docks showing examples of real-world objects in the Structures theme." width="563"><figcaption><p>Examples of real-world objects in the Structures theme.</p></figcaption></figure>

#### Physical features in the Structures theme include:

* Stand-Alone Monuments
* Fountains
* Covered Reservoirs
* Pylons
* Weirs and Sluices
* Gas Holders
* Double Walls
* Pontoons
* Uncovered Tanks
* Conveyors
* Cooling Towers
* Upper Levels of Communication
* Bridges, Viaducts, Aqueducts, and Piers Non-physical features are represented by text.


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