Identification info

Metadata Language

English

Character set

UTF8

Dataset Reference Date (Creation)

2007-04-01

Identifier

www.gov.scot / SG_MarinePlanningZones

Presentation form

Digital map

Maintenance and update frequency

Unknown

GEMET - INSPIRE themes, version 1.0

• Area management/restriction/regulation zones and reporting units

IPSV Subjects List

• Marine environment

Limitations on Public Access

Other restrictions

Other constraints

No limitations to public access

Use constraints

Other restrictions

Other constraints

Open Government Licence

Other constraints

The following attribution statement must be used to acknowledge the source of the information: Copyright Scottish Government, contains Ordnance Survey data © Crown copyright and database right (insert year)

Spatial representation type

Vector

Topic category

• Boundaries
• Oceans

Code

S92000003

Additional information

http://www.scotland.gov.uk/Publications/2005/10/27171805/18056

 

Code

EPSG:4258

Code

EPSG:27700

Distribution Information

 

Data quality info

Quality Scope

Dataset

Statement

This sets out a technical description of the method used by the UKHO to construct the marine boundaries consulted on in this document. External boundaries The Water Environment and Water Services (Scotland) Act 2003 ("the WEWS Act"), provides for planning authorities to have statutory planning powers within coastal and transitional waters i.e. out to the 3 mile limit. Section 3(9) of the WEWS Act defines the "3 mile limit" as "the limit consisting of a line every point of which is at a distance of 3 miles on the seaward side from the nearest point of the baseline (see paragraph 14 below) from which the breadth of the territorial sea of the United Kingdom adjacent to Scotland is measured; and "miles" means international nautical miles of 1,852 metres." The planning authority marine zones therefore extend to the 3 mile limit. The territorial baseline around Scotland is the data set from which the breadth of the territorial sea of the United Kingdom, adjacent to Scotland, is measured. The baseline is formed by the low-water line along the coast and a series of straight baselines. These straight baselines are required in areas where the coastline is deeply cut into, where there is a fringe of islands along the coast or where the coastline is unstable. Waters on the landward side of the territorial baseline are termed internal waters. This means that around the Minch and the Sea of Hebrides, as the 3 mile limit is measured from the baseline, it results in the outer limit of waters attributed to local authorities in these areas extending further from the shore than 3 nautical miles and at times reaching more than 15 nautical miles.

Definition of Median Lines: Essentially the construction approach involved a two-stage process. The first stage required the calculation of median lines based on the UKHO low water line data. These "median lines" were calculated from the low water line data to ensure that they are always equidistant from the coast on either side of the line, thus taking coastal geography into account and providing an equal division of the water between local authorities out to the 3 mile limit. The second stage required these median lines to be fitted to the OS coastline data, so that the dataset representing the marine areas assigned to each authority would snap directly to the OS land boundary shape files provided. The median lines were generated mathematically using points on the UKHO low water line, with the digital data for the low water line being processed in Universal System's CARISLOTS®. To begin the process, the low water line for each side of the median line had to be clearly defined, and this required a split to be made in the UKHO low waterline data base at the terminus of the land boundary. The difference between UKHO low waterline and OS coastline meant that an approximation was required to achieve such a split. This approximation was arrived at by drawing a perpendicular to the general direction of the UKHO low waterline, through the land boundary terminus, and then splitting the UKHO low waterline at the point of its intersection with the perpendicular. Once this split was made, the separate elements of the UKHO low waterline model could be used to generate a median line; with the origin of the median line being the point where the UKHO low waterline data was split. Median lines calculated from a digital model of the low water line use the precise, high density model of the UKHO low water line. As a result, the median lines generated mathematically from this model contain a very large number of turning points (555 miles of marine boundary were defined by around 15,000 data points). Having calculated the median line, the UKHO then "closed" the line to the OS coastline data so that the authority marine boundary would begin at the point where the OS-designated land boundary ended. To achieve this, the part of the median line between the split in the UKHO low water line model and the land boundary terminus was manually edited to snap to the perpendicular described above. The data was then exported from CARISLOTS to Microimages' TNT Mips® to close the provisional median line to the authorities' shape file. A further snapping of no more than 0.6 to 0.8 metres was necessary to close these shapes to the initial data. The UKHO explained this last adjustment as being "likely to arise from differing datum transformation parameters [ CARISLOTS used to generate median lines and limits only works on WGS84 but the final adjustment is made in TNTMIPS so minor errors in datum shift do not affect the result]". The movement caused by the approximations used in the construction outlined above was generally along the line of the median line or the authority boundary, and so minimised the change to the direction of the marine boundary. Whilst the discrepancy between OS coastline and UKHO low waterline varies from a few tens of metres on the open coast to as much as 2-300 metres in rivers, the method used by UKHO to adjust the median lines onto the OS coastline means that the lateral displacement of the boundary is between only 5 and 10 metres.

Low tide elevations and Islands: Low tide elevations are areas charted on UKHO charts as land that is only visible at low water. The low water line surrounding such features is part of the UKHO low water line data base. The occurrences of detached charted features that are not visible at high water have been ignored and no effort has been made to re-route boundaries round these features. As a result, there are instances within rivers where two neighbouring authorities share jurisdiction over sand bars or other minor features that are only visible at low tide. The treatment of islands and low tide elevations in this project ensures that the median lines are only influenced by the islands contained in the OS data. All islands contained in the information provided were attributed to an individual local authority. These islands were accorded full weight in the development of boundaries. No work was undertaken to simplify or reduce the effect of small islands.

Loch Lomond and the Trossachs: The only area where a slight amendment to this technique was required was at Loch Lomond and the Trossachs National Park, where the National Park coastline (as defined in statute) did not match the OS coastline data precisely. The Executive advised that the marine space ascribed to Loch Lomond and the Trossachs should close on the OS coastline data, thus requiring an adjustment at each of the terminal marine boundary points, with adherence to the OS coastline data at all points in between. The construction of the median lines was achieved using precisely the same method as for local authority boundaries, but in this case the median line start points were snapped to the node on the OS coastline model closest to the point where the Park Authority boundary diverts inland from the coast. The UKHO reported, however, that the divergence in relevant areas of the OS coastline data and the National Park shape file coast was only 1-2 metres, and as such was "not significant". Further details can be found here - http://www.scotland.gov.uk/Publications/2005/10/27171805/18056. Two further minor amendments were made. The boundary of Argyll and Bute Council at the mouth of the River Echaig and at Loch Shira followed that set out in OS BoundaryLine 2005.

 

Metadata

File identifier

991b58b2-b632-46c1-939b-4f480617ae9c XML

Metadata Language

English

Resource type

Dataset

Metadata Date

2021-01-14T13:21:40

Metadata standard name

UK GEMINI

Metadata standard version

2.3