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SSGP High Resolution Data Initiative SEDAS User Guide
SSGP High Resolution Data Initiative
SEDAS User Guide
UK SPACE AGENCY- SPACE FOR SMARTER GOVERNMENT PROGRAMME
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Author: Simon Agass, Lead Applications Technologist
Date: 14 February 2019
Version: V1.
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Table of Contents
Background ............................................................................................................................................. 1
Technical Note ........................................................................................................................................ 2
Registering as a user. .............................................................................................................................. 3
How to search for SSGP data on SEDAS? ................................................................................................ 6
Searching Geographically .................................................................................................................... 6
Searching Temporally.......................................................................................................................... 7
Advanced Searching by sensor or project........................................................................................... 7
Interrogating a product ......................................................................................................................... 10
Downloading a Product ......................................................................................................................... 11
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Background
he UK Space Agency’s (UKSA) Space for Smarter Government Programme (SSGP) works with UK
companies, institutions and government departments to communicate, facilitate and
demonstrate the value of satellite derived applications to the new wave of government services.
To allow government departments to work with and understand what information can be derived
from satellite systems, SSGP has competitively procured archive satellite data a significant portion of
the UK for R&D purposes from two data providers to enable access to an unprecedented amount of
high-resolution satellite imagery.
What data is available?
The satellite data included as part of this initiative will include optical data from Airbus Defence and
Space and Synthetic Aperture Radar data from Telespazio Vega UK Ltd.
Optical Data
The optical data (including options) could include data from the following satellites and at the
following resolutions.
Satellite Data Resolutions
Pleiades Pan or Colour 50cm
TripleSat Pan or Colour 80cm
Pleiades MS 2m
SPOT6/7 Pan or Colour 1.5m
TripleSat MS 3.2m
SPOT6/7 MS 6m
DMC Constellation MS 22m
SAR Data
The SAR data (including options) will include data from the following satellites and at the following
resolutions.
Satellite Data Resolutions
CosmoSkyMed Stripmap HIMAGE 3-5 m
CosmoSkyMed Spotlight ≤ 1m
CosmoSkyMed Stripmap Ping Pong 15m
CosmoSkyMed WideRegion 30m
CosmoSkyMed HugeRegion 100m
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Who can use the data?
The satellite imagery has been purchased under a cross government multi user, research and
development license allowing the government end user to work partner companies to develop,
demonstrate and test applications. The data being purchased as part of this contract will be made
available to support the development of ideas, data challenges and projects and will includes up to
three years of archive imagery (initially from the contract let date) covering Great Britain and Northern
Ireland including up to three miles off shore.
Technical Note
The SSGP data procurement has been split into two categories of data, optical and radar.
Optical data is a derivative of a passive satellite sensor, like a normal camera, an optical sensor
measures the sunlight refracted through the earth’s atmosphere and off the surface of the earth and
up to the satellite. The resulting data in bands of red, green and blue forms an image in true colour
and represents the surface of the earth from where the light is bounced, an image similar to a digital
photograph is produced. On the majority of satellites data is also collected in a range of wavelengths
such as near infrared for example, enabling the satellite to see bands of light not visible to the human
eye. Using analysis techniques, it is possible to determine such information as the health of a crop,
the height of a structure and exposed geology of a landscape for example plus many other
applications.
Radar data is the product of an active satellite system. An active satellite transmits a signal in the form
of a wave length that is reflected off the surface of the earth and collected as backscatter by the same
satellite as it transits through its orbit. As the backscatter interacts with objects and vegetation on the
surface it reflects in slightly different ways enabling the resulting backscatter to then be processed to
produce an image of the surface of the Earth. Radar satellites work in different modes which often
represent the width of the image attained and each satellite is dedicated to working in a different
band width, with x band having a 2.5cm band width meaning it can interact with smaller objects on
the earth’s surface and there for show finer detail. A Radar satellite has the benefits of not being
affected by cloud however the image does not detect colour in the same way an optical image does
so the image will be returned in black and white. Some typical applications for a radar satellite are,
ground movement, surface water identification, crop phenology and change detection however far
more applications are available.
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Registering as a user.
To access the SSGP data, the data has been made available through the Sentinel Data Access Service
(SEDAS) on http://sedas.satapps.org pictured below.
To access the data a user must be registered on SEDAS, approved by the SSGP and have returned a
Data Access Form and signed End User Licence Agreement (EULA) prior to access being granted.
The system can be access by clicking on the “Latest Data” button highlighted below.
Once the web map application has loaded the following screen will appear.
This will provide you with access to the SEDAS system as a “GUEST” user. You will not be able to
access the SSGP content as a “GUEST” full registration is required prior to access.
To register as a user of SEDAS you will need to complete registration by clicking on the “GUEST” drop
down menu on the top right hand side of the screen as highlighted below.
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Once the drop down menu is open you are presented with two options, either to “Sign In” or “Sign
Up”
If you are new to SEDAS press the “Sign Up” button to continue
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Once the “Sign Up” button has been pressed, the following form will load.
To create an account, complete the form. To access the high-resolution data being made available
through the Space for Smarter Government Programme, ensure that you tick the SSGP box under
the projects section of the form as highlight above. To complete the registration, click the “Create”
button.
Completing the above will automatically create an account for the SEDAS system, enabling you to
search, view and download the European Commission Sentinel Data. In order to access the SSGP
data approval is required from the SSGP team, until the Data Access Form and End User License
Agreements have been returned and registered by the team, the SSGP data will remain inaccessible
to the end user, and no SSGP data will be returned in the search results.
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How to search for SSGP data on SEDAS?
Searching Geographically There are a number of different ways of searching for data in the SEDAS portal. This can be done
Geographically, through the use of a place name, or by defining a boundary of some description
using a box, polygon, circle or by importing a previously used area of your own making, this can be a
.shp file, a kml or kmz extension file.
These options are exposed by clicking on the “SEARCH FOR DATA” tab on the top left-hand side of
the screen, as illustrated below.
IN ORDER TO ENABLE THE SSGP DATASETS THE “ENABLE UK SPECIFIC DATASETS” CHECKBOX MUST
BE CHECKED.
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Searching Temporally The second part of the search that needs to be defined is the temporal range or date for which you
want to search the catalogue for data.
By clicking on the “date” tab as illustrated below a date picker appears on the screen.
Using the date picker tool it is possible to either selected a pre-defined range of dates, such as “Last
year”, “Last month”, “Last 7 days” or “Last day” or define your own range of dates beginning and
ending on dates of your choosing.
If you run a search at this point you will return results from all sensors and all projects.
To refine the search further “Advanced Search” is required.
IN ORDER TO ENABLE THE SSGP DATASETS THE “ENABLE UK SPECIFIC DATASETS” CHECKBOX MUST
BE CHECKED.
Advanced Searching by sensor or project.
In order for the system to return a more specific requirement or set of data it is required that the
user enter some more advanced parameters into the “Advanced Search” selection menu.
The “Advanced Search” menu can be accessed by clicking on the down arrow next to the “Run
Search” button in the top middle of the screen, as illustrated below.
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And by clicking on the “Advanced Search” button.
Once the “Advanced Search” menu appears the user is presented with different parameters with
which to filter the search on. This ranges from which sensor through to percentage cloud cover and
orbital direction.
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However, for the user to simply access the high resolution imager available through the Space for
Smarter Government Programme, the user only needs to select “SSGP” from the “Project” drop
down and click “Apply”
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Interrogating a product By selecting the various buttons underneath each search result it is possible to find out more
information about each image, overlay it onto the map and add it to your basket.
Above: Adding the quicklook to the map and zooming to the extent of the product.
Above: Opening the product in a new window.
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Above: Viewing the metadata of a product.
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Downloading a Product
To download a product, the user must first add it to their basket.
This is achieved by clicking on the basket icon that appears under each search result.
Once added to the users basket a dialogue appear to inform the user that the image is ready to be
downloaded.
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The user can simply choose to download the selected image from the portal by clicking on the
download icon, remove the selected image from the basket by clicking on the bin icon
or continue to search and add additional images to the basket.
If you encounter any problems accessing the SSGP data having followed these instructions, please
contact the SSGP team on [email protected] and we will endeavour to answer your query
as quickly as possible.
