GeoIndex help | Landsat map theme

View the Landsat map theme

Click on the links below for further information about the available datasets.

TM landsat imagery

This satellite data is shown at different resolutions depending on the current map scale. At small scales, it is shown in generalised form with each pixel covering 300 metres, and at larger scales it is shown at its actual resolution of 30 metres.

The satellite imagery in GeoIndex was acquired by the Landsat Thematic Mapper sensor between 1984 and 1990. The imagery has been processed by the BGS Remote Sensing Section to increase contrast and thus enhance natural boundaries. Winter imagery was chosen due to the low sun angle, which enables geomorphic features on the landscape to be distinguished and interpreted. Geomorphic features include surface landforms, such as faults in Bedrock and drumlins in Superficial deposits. This imagery has proven useful to geologists when mapping these features in isolation and when determining both regional and local patterns. For example, the drumlin field in the Solway area, at Carlisle, is clearly visible in the imagery, while individual drumlins can also be mapped with ease at a larger scale.

The colours in the image are not what one would normally expect to see because we have used infrared wavelengths to help us extract more geological information than would be possible if we had used visible bands (i.e. as the human eye would see the landscape from space). For example, the bright red colour on the mountains in Scotland is snow, while the blue areas are generally urban regions, exposed rock, and bare soil. In winter, most UK vegetation contains the same amount of water so it is difficult to distinguish between vegetation types, the notable exception being coniferous forestry which has a rust-brown colour. While this may appear to be a limitation of the data it is preferable because the patchwork quilt effect of agricultural fields camouflages the geological information that we seek to extract.

To create a single image of the whole country, many smaller images covering different rectangular areas and taken at different dates have been patched together. This will in some cases produce marked changes where the smaller images meet, and is due to the different conditions when the images were taken.

Raw imagery © EOSAT/Eurimage. BGS processed and enhanced imagery © NERC. All rights are reserved by the copyright proprietors.

Superficial deposits 1:625 000 scale

The 'Superficial deposits' shown on the GeoIndex map includes the youngest geological deposits laid down in England and Wales, Scotland and part of Northern Ireland. This map is based on the first edition Drift 1:625 000 scale Geological Map of the United Kingdom published in 1977 as two sheets, North and South, available from the BGS Internet Shop.

The Superficial deposits, mainly formed in the Quaternary period of geological time, which extends from the present back to 2 million years ago. Many of the deposits were formed during episodes of glaciation ,or deposited by rivers. They occur as discontinuous patches and larger spreads and rest on top of the older rocks (referred to in the Bedrock).

Most of these Superficial deposits are unconsolidated sediments such as gravel, sand, silt and clay. The name of each deposit or group of deposits corresponds to that shown on the published 1:625 000 map e.g. River Terrace Deposits.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1977. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Faults 1:625 000 scale

Digital geological dataset depicting the faults only of the bedrock geology of the United Kingdom at surface/rock head.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Dykes 1:625 000 scale

Digital geological dataset depicting the dykes only of the bedrock geology of the United Kingdom at surface/rock head.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Bedrock 1:625 000 scale

The 'bedrock' shown on the GeoIndex map comprises the bedrock geology, which represents the outcrops (at surface) and subcrops (at near-surface, beneath superficial deposits) in England and Wales, Scotland and part of Northern Ireland. It is based on the third edition Solid 1:625 000 scale Geological Map of the United Kingdom published in 1979 as two sheets, North and South. These sheets are available from the BGS Internet Shop.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276