The following content details the technical
specifications of the GIS data, including licensing, data format,
metadata, and data accuracy.
A data licence will need to be agreed before the data may be
downloaded. The licence will ask you to accept certain terms and
conditions attached to the use of the data.
All of the datasets are available for download in either MapInfo
.Tab or ESRI .shp format.
All of the datasets supplied will be accompanied by metadata
detailing scale/resolution, date of capture, attribution notes etc.
CCW has adopted the GEMINI2 metadata standard, and the
metadata, which is distributed with the GIS data, is
available in our OLIB Library Catalogue.
The boundary of the Site defines the extent of the area of
Protected land. There may be excluded areas within the Site
The Site boundary may follow a feature mapped on the Ordnance
Survey (OS) map, such as a hedge or stream, or it may be
'undefined'. It may follow a feature such as the Mean Low Water
mark, which is liable to change.
- Basic Scale of Data Capture
have been digitised using the OS MasterMap 1:2500 or to the OS
1:10000 digital raster as a guide.
This information is attributed in the data tables.Using the data,
for mapping, or in a GIS, at scales other than those above may
result in unpredictable results.
- Coordinate Systems
The data is captured
using the Cartesian coordinate system on the British National
- Accuracy of Digitised Line
OS MasterMap has been used to capture data against it is
snapped to each node, where appropriate.
Then data is captured against against OS 1:10000 raster, the aim is
+- 0.2 mm, based on the old cartographic drawing standard in the
days of pen and ink, which translates to 0.5 metres on the ground
when used to produce maps at 1:2500 scale.
- Quality Assurance
Digitisation is carried
out using controlled environments to ensure correct topology. Plots
are made and checked against source material.
- Positional Accuracy Improvement (PAI)
of our Protected sites datasets have now been corrected to meet the
For more details about PAI please see the Ordnance Survey