Data Archives - FAQ
The Landmap Data Archive aims to provide systematic complete coverage of the UK for both Radar and Optical data over the next five years thanks to the financial support of JISC.
What is the Landmap Service?
What are data archives?
What is meant by Optical, Radar and Elevation data?
Where have the data come from?
Does the service have accompanying metadata for the imagery?
How do I access the metadata?
Q. What is the Landmap Service?
A. The Landmap Service is hosted by Mimas based at the University of Manchester and funded by JISC. Landmap supports the UK academic community to access and use value-added satellite and airborne datasets for cutting edge research and teaching.
A. Data archives provide resources to analysts, learners and researcher who want to use data for teaching and research. The Landmap Service has a geodata archive which consists of four collections these are:
- Optical & Thermal Collection: Includes orthorectified Landsat 4/5; Landsat 7 and SPOT imagery; Mediterranean Landsat data; Colour Infrared; TopSat; Modern and Historic Aerial Photography; Thermal imagery.
- Radar Collection: Includes ERS 1; ERS 2; ENVISAT ASAR (IMage Mode, Alternating Polarisation, Wide Swath)
- Elevation Collection: Includes 75m SRTM; 25m DTM; 5m Bluesky DTM
- Feature Collection: Building Heights and Building Class data for the main conurbation in the UK.
- ensuring that geodata are preserved against technological obsolescence and physical damage
- checking, validating, preparing geodata and accompanying user documentation
- supplying geodata in an appropriate from to secondary users
Q. What is meant by Optical & Thermal, Radar, Elevation and Feature data?
A. Optical & Thermal data - optical data should as Landsat and SPOT are affected by atmospheric influences such as cloud cover, usually an atmospheric correction must be applied to the satellite image before use. Both Landsat and SPOT data are the most widely used medium-resolution, remotely sensed data for regional applications. Colour Infrared data at Landmap contains the Red, Green and Infrared bands, this data is very useful for assessing crop health. The TopSat data is not georeferenced and consists of an archive of images collected from 2007 - 2009 from around the world, researchers have found this data very useful for planning fieldwork. Modern Aerial Photography and Historic Aerial Photography and concentrated on the main urban conurbations around the UK (however you will find some exceptions such at a collection of RSPB site aerial photographs over their reserve areas). Thermal imagery can be used to assess the relative heat loss of buildings this data covers the main conurbations in the UK.
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Q. Where have the data come from?
A. The Landmap service provides 3 different satellite imagery dataset. These are: Optical Data which is acquired by Infoterra and CNES. Radar Data which is acquired by European Space Agency (ESA). Elevation which originated from the Shuttle Radar Topography Mission (SRTM), Kinematic Global Positioning System (KGPS) and a 25m DEM derived from ERS 1 & ERS 2 data acquired from ESA.
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Q. Does the service have accompanying metadata for the imagery?
A. Yes, all of imagery comes with XML metadata format. Landmap service follows the Federal Geographic Data Committee's (FGDC) ESRI metadata format.
Q. How do I access the metadata?
A. There is no online access to the metadata for the Landmap data archive; however metadata is supplied with the data during the download process. Alternatively we can send metadata on request in XML format if you email to the helpdesk. The service is looking to provide a metadata search facility over the next six months.
