OS 1:10,000 Large Scale Mapping

OS 1:10,000 Mountain & Moorland Base Scale Mapping

1:10,000 scale is the smallest of the 3 base scales used by the Ordnance Survey (OS) in producing their Large Scale Mapping products covering the whole of Britain. Currently, this base scale has a more limited specification for data capture than the other two base scales in use, and incorporates a higher degree of generalisation. The landscapes surveyed by OS at 1:10,000 scale include:

Lowland agriculture, settlement, transport and industry – for example, farmhouses, steadings, hamlets, updated infrastructure, crofts and settlements

Upland agriculture & industry – for example, wind farms, farms, whisky distilleries and managed forests

Open moorland and mountain-scape - for example, Estates, salmon fishings and wind farms.

Applications received by the Keeper for registration that fall within this mountain and moorland setting, or 1:10 000 scale mapping, are often high value, high profile casework; for example, large estates or wind farms. Often, these applications are also very complex; for example, they comprise large estates with numerous exceptions, or include salmon fishings or leases of sporting rights. Some, however, are registrations of single houses or crofts, and although small in size they can be tricky to map correctly onto the 1:10,000 base scale map. It is vital, going forward, that we get it right for both the applicant and the Keeper since protecting the individual's rights, and the Keeper's warranty and reputation, are vital for the integrity of the land register. So although we receive small numbers of applications in these areas, they are, nevertheless, extremely important.

Currently, the OS are considering a possible upgrade to their 1:10,000 base scale maps - see OS 1:10,000 Base Scale Mapping - Possible Upgrade for more information.

1:10,000 scale OS coverage in Scotland

Coverage of 1:10,000 areas in Scotland is shown coloured orange in this image.

63% of Scotland is affected by 1:10 000 mapping but, to date (2014), only 1% of registered titles (approximately 11,000 titles) are within these areas.

1:10,000 Scale OS Tolerances

Base Scale	1:10,000, Mountain & Moorland
Positional Accuracy	+/- 4.1m
Minimum separation between features	5m
Minimum feature size (buildings, vegetation)	Vegetation over 1.0 hectare and 10m wide Buildings with a minimum dimension of 5m
Cartographic features (text & symbols	All appear approximately 4 times larger than on 1:2500 scale Rural mapping

These specifications result in a generalised map which can cause problems when compared with deed plans prepared using modern technology, where surveyors can prepare very high quality plans using GPS.

1:10,000 Scale OS Map Generalisation

Cartographic Generalisation is the process of simplifying and improving the legibility of maps with the aim of improving legibility. Generalisation is used to emphasise, simplify, select and sometimes omit features to produce a cartographic representation of the landscape at a scale of 1:10,000.

This image is an example of 1:10,000 OS map detail (red lines) superimposed on aerial imagery.

Generalisations -

The building at the top is shown as a simple rectangle as the mapping at this scale does not show juts which are apparent on the aerial imagery
Roadway has been widened & generalised
The location and angle of the small outbuilding next to the road is inaccurate
The jut in the front of the building at the bottom of the image is too small to be depicted.

In this example we can see that the angle of the buildings is not accurately reflected on the OS map, the divisional walls are not shown and it looks like one property.

When we are considering the mapping of any registration we must consider:

Is the OS map an accurate reflection of the detail on the ground? (This is particularly important if we are plotting any features since plotting off from the road or buildings could be misrepresentative)
Can the legal extent be reconciled with the Ordnance Map?
If the answer to either question is no, consideration should be given to requisitioning a survey of the area using the Form P24 survey request process (see here for advice on completing the P24 form). Discuss with a Plans RO1 or Plans SCW.

Transition between map scales - specification comparison

In this image we see an example of where a 1:10,000 scale map meets a 1:2500 scale map. The process of blending one specification into another at the edge of the two differently-scaled maps is known as "feathering".

Points to note -

The river has changed from single line on the 1:10,000 scale map to a more realistic double feature on the 1:2500 scale map
The roadway which is hugely exaggerated on the 1:10,000 scale map is now representative of the actual width on the ground on the 1:2500 scale map.

If feathering affects your application, consideration should be given to whether or not it affects your ability to accurately reflect the legal boundary. If it does prevent you accurately mapping the legal extent (within the published tolerances), you should discuss with a Plans RO1 or Plans SCW if it is appropriate to submit a Form P24 survey request for the area. See here for advice on completing the P24 form.

What do I do if the deed plan is more detailed than the OS 1:10,000 scale map?

Sometimes an applicant will submit a deed plan that is sufficient to identify the property but it cannot be reconciled with the features on the OS 1:10,000 base map held by the Keeper. An example could be a rural property where the OS base scale is 1:10,000 and is not generally up to date. The deed plan submitted by the applicant has been produced at a better scale and shows more up to date detail that cannot be reconciled with our version of the OS.

If after discussion with a Plans RO1 or Plans SCW, it is decided that the application cannot proceed using the 1:10,000 base map held by the Keeper, a Form P24 survey request should be made to mapbase maintenance (see here for advice on completing the P24 form). Once the P24 has been submitted, the application should be placed into standover until the survey results are received. This usually takes around 2-3 weeks for mainland Scotland, but can be longer for the islands.

Useful Links

OS 1:10,000 Base Scale Mapping - Possible Upgrade