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OS Sitemap®

Technical information

OS Sitemap is the most detailed digital mapping of Great Britain in site-centred form.

TIFF / Paper example click here

DXF example click here

The very latest available survey information

We make nearly 8 000 updates everyday, so you can be sure of getting the very latest map.

Site-centred

Your site or property is put at the centre of the map, giving a clear picture of its relation with the surrounding area.

Nationwide coverage

From city centres to upland moors, OS Sitemap provides map extracts for any location in Great Britain.

Customised mapping

OS Sitemap is available in hard copy and electronic media. These are:

  • Paper (a printed hardcopy)
  • Tagged Image File Format TIFF
  • Data Exchange Format DXF™

Up to 60 layers

With so many variables available, you can remove features you do not need, creating a cleaner and more focused way of working.

Levelling and height information

OS Sitemap provides spot heights and identifies bench mark positions to help provide an appreciation of the 3rd dimension. For DXF users, feature coordinates include a 'z' value attribute (set to zero).

CAD compatible

Because OS Sitemap is supplied in DXF level 1, it is compatible with most popular CAD systems.

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Scale and source

The area you define can be a site-centred pocket of mapping within one National Grid (NG) sheet or across several sheets and source survey scales. The minimum ground area covered for any order is 1 hectare for DXF data and 4 hectares for TIFF data and plots. The maximum ground area you can purchase is dependent on the source scale and desired output scale. If the majority (51% or more) of the area you define is 1:1250 scale data, the limit in any one order is 250 hectares. If the majority is 1:2500 scale data, the limit is 1 000 hectares and if an order is 80% or more of 1:10 000 scale data, the limit is 22 500 hectares.

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Survey Accuracy

 

Absolute accuracy compared with the National Grid. Absolute error - Root Mean Square Error (RMSE)

Absolute accuracy

99% confidence level

Relative accuracy

Distance between points taken from the map. Relative error.

Relative accuracy

99% confidence level

1:1250 (urban)

0.5 metres

<0.9 metres

+/- 0.5 metres

(60 metres)

<+/- 1.1 metres

(60 metres)

1:2500 resurvey of reformed (urban and rural)

1.1 metres

<2.4 metres

+/- 1.0 metres

(100 metres)

<+/- 2.5 metres

(100 metres)

1:2500 overhaul (urban and rural)

2.7 metres

<5.8 metres

+/- 1.9 metres

(200 metres)

<+/- 4.7 metres

(200 metres)

1:10 000 (mountain and moorland)

4.1 metres

<8.8 metres

+/- 4.0 metres

(500 metres)

<+/- 10.1 metres

(500 metres)

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