Satellite Image Data Service

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Invited speaker at the University of Nottingham, School of Geography Research Seminar

Invited speaker at the University of Nottingham, School of Geography Research Seminar

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  • A Web Map Service produces maps of spatially referenced data dynamically from geographic information. This International Standard defined a map to be a portrayal of geographic information as a digital image file suitable for display on a computer screen. A map is not the data itself. Rendered in a pictorial form such as PNG, GIF or JPEG. 3 operations – one returns service-level metadata GetCapabilities - returns a map whose geographic and dimensional parameters are well defined GetMap - optional third returns information about particular featured shown on a map GetFeatureInfo The OGC Web Feature Service allows a client to retrieve and update geospatial data encoded in Geography Markup Language (GML) from multiple Web Feature Services. The requirements for a Web Feature Service are: 1. The interfaces must be defined in XML. 2. GML must be used to express features within the interface. 3. At a minimum a WFS must be able to present features using GML. 4. The predicate or filter language will be defined in XML and be derived from CQL as defined in the OpenGIS Catalogue Interface Implementation Specification. 5. The datastore used to store geographic features should be opaque to client applications and their only view of the data should be through the WFS interface. 6. The use of a subset of XPath expressions for referencing properties The Web Coverage Service (WCS) supports electronic interchange of geospatial data as "coverages" – that is, digital geospatial information representing space-varying phenomena, allows clients to choose portions of a server's information holdings based on spatial constraints and other criteria. Unlike WMS which filters and portrays spatial data to return static maps (rendered as pictures by the server), the Web Coverage Service provides available data together with their detailed descriptions; allows complex queries against these data; and returns data with its original semantics (instead of pictures) which can be interpreted, extrapolated, etc. -- and not just portrayed. Unlike WFS which returns discrete geospatial features, the Web Coverage Service returns representations of space-varying phenomena that relate a spatio-temporal domain to a (possibly multidimensional) range of properties. Three operations: GetCapabilities, GetCoverage, and DescribeCoverage. The GetCapabilities operation returns an XML document de-scribing the service and brief descriptions of the data collections from which clients may request coverages. The DescribeCoverage operation lets clients request a full description of one or more coverages served by a particular WCS server. The server responds with an XML docu-ment that fully describes the identified coverages. The GetCoverage operation of a Web Coverage Service is normally run after GetCapa-bilities and DescribeCoverage replies have shown what requests are allowed and what data are available. The GetCoverage operation returns a coverage (that is, values or prop-erties of a set of geographic locations), bundled in a well-known coverage format. Its syntax and semantics bear some resemblance to the WMS GetMap and WFS GetFeature requests, but several extensions support the retrieval of coverages rather than static maps or discrete features. A Web Processing Service provides a client access across a network to pre-programmed calculations and computation models that operate on spatially reference data. The calcualtion can be extremely complex or simple with any number of data inputs and outputs. To achieve interoperability each process must be defined in a separate document ‘Application Profile’.

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  • 1. Satellite Image Data Service: Providing Satellite Data Online for the UK Academic Community Gail Millin Geodata Interoperability Support Officer The University of Nottingham School of Geography Research Seminar 13th December 2006
  • 2. 13th December 2006 Satellite Image Data Service 2 Presentation Outline  Introduction to Satellite Image Data Service  Organisation  Data archive  Development Activities  Image Processing of ASAR data  Extending Data Access Infrastructure  Learning Materials  Image Processing Course  Future Work and Goals  Expand Current Data Holdings  Extending Web Mapping Clients  Proposal to JISC for 5 Years Funding
  • 3. 13th December 2006 Satellite Image Data Service 3 Introduction to SIDS
  • 4. 13th December 2006 Introduction to the Satellite Image Data Service4 MIMAS Organisation
  • 5. 13th December 2006 Introduction to the Satellite Image Data Service5 Satellite Image Data Service (SIDS)  Supports a large geographic data resource  Available to academics attending an institute that has paid a JISC data hosting charge.  Web-based access to a range of satellite imagery for the British Isles for research and teaching purposes:  Landsat 5 (late 80’s early 90’s) & Landsat 7 (1999 – 2000)  Mediterranean data (Landsat imagery only)  SPOT (mid 1990’s)  ERS 1 & 2 (1995 – 1999)  Raw Satellite Data Archive of the above  ENVISAT ASAR – AP, IM & WS (2005 – 2006)  Landmap 25m DEM (derived from ERS) and Georeferenced SRTM
  • 6. 13th December 2006 Satellite Image Data Service 6 Satellite Data Available!
  • 7. 13th December 2006 Introduction to the Satellite Image Data Service7 Landsat 5 & 7  Projected to British National Grid  64 multi-spectral TM images each scene contains 7 bands and 8 bands for Landsat 7 for 180km x 160km coverage  30m, 25m and 15m L7 panchromatic  JPEG, GeoTiff, Imagine
  • 8. 13th December 2006 Introduction to the Satellite Image Data Service8 SPOT  Projected to British National Grid  150 Panchromatic images available  10m resolution 60km x 60km coverage  ECW & GeoTiff format
  • 9. 13th December 2006 Introduction to the Satellite Image Data Service9 New ENVISAT ASAR Alternating Polarisation ©ESA,2004 Image Mode ©ESA,2005 Wide Swath ©ESA,2005
  • 10. 13th December 2006 Introduction to the Satellite Image Data Service10 Landmap ERS & DEM
  • 11. 13th December 2006 Introduction to the Satellite Image Data Service11 Data Provision  Seasonality  Managed 500GB of data and provides a data portal  No copyright – share results freely  Decrease expensive for users and negotiations of licenses done on users behalf  High quality metadata (updated 2006-07) – XML  Can be used for a wide range of applications  Geomorphology Mapping (Smith et al., 2006)  Hydrological Modelling (Bundela, 2005)  Land Cover Classification (Clack, 2004)
  • 12. 13th December 2006 Satellite Image Data Service 12 Image Processing
  • 13. 13th December 2006 Development Activities - ASAR Image Processing13 Data Aquisition STEP 1 – Get Data from European Space Agency
  • 14. 13th December 2006 Development Activities - ASAR Image Processing14 SARScape Chosen due to : • Ease of Use – GUI • Good user support • Instructor led course • Plugs into ENVI 4.1 • View orthorectified product directly • Supports all three ASAR modes STEP 2 – Identify Specialised software
  • 15. 13th December 2006 Development Activities - ASAR Image Processing15 Image Processing Chain STEP 3 – Create an Image Processing Chain
  • 16. 13th December 2006 Development Activities - ASAR Image Processing16 Advanced Synthetic Aperture Radar Alternating Polarisation ©ESA,2004 Image Mode ©ESA,2005 Wide Swath ©ESA,2005 STEP 4 – View Processing Outputs
  • 17. 13th December 2006 Development Activities - ASAR Image Processing17 Colour Composite ASAR  ASAR imagery, British Isles coverage, GB National Grid and Irish Grid Coordinates.  Provided in WMS and WCS services for  Image Mode (IS2 Swath),  Alternating Polarisation,  Wide Swath Future Work Provide data at different times of the year – seasonality  Create Coherence Colour Composite Multi Images and interferograms.  Provide on-line learning support materials for ASAR data Image Mode Coherence Colour Composite STEP 5 – Derive Further Datasets
  • 18. 13th December 2006 Satellite Image Data Service 18 Interactive Mapping
  • 19. 13th December 2006 Development Activities - Data Access Infrastructure19 OGC Services  Open Geospatial Consortium (OGC) - a non-profit, international, voluntary standards organization, leading the development of standards for geospatial services  OGC founded in August 1994 and includes a wide range of vendor members, universities, state agencies and federal agencies  Aim is to advance geo-processing interoperability across the GIS industry  Web Map Services (WMS)  Web Feature Services (WFS)  Web Coverage Services (WCS)
  • 20. 13th December 2006 Development Activities - Data Access Infrastructure20 What is Interoperability?  One does not have to adopt the same format to be interoperable!  Interoperability aims to adopt a negotiating system to understand a wide range of formats e.g. WMS, WFS and WCS ‘one should actively be engaged in the ongoing process of ensuring that the systems, procedures and culture of an organisation are managed in such a way as to maximise opportunities for exchange and re-use of information, whether internally or externally’ Paul Miller, University of Hull  At the SIDS WMS provide an alternative to the traditional download area of the website and potential to exchange data with other academic institutions
  • 21. 13th December 2006 Development Activities - Data Access Infrastructure21 Justification  SIDS can better utilize the imagery in the archive  Increase visibility to an increasingly sophisticated user community, reducing the need to contact the SIDS by more traditional means e.g.  Telephone  In writing  Working on-line with traditional point and click download interface  By the SIDS abiding by OGC specifications our service can be an interoperable organization with others, increasing the potential usability of the service.  The SIDS can still maintain our own unique branding within the Portals through which the content is available e.g. Customized Chameleon OGC Viewer.
  • 22. 13th December 2006 Development Activities - Data Access Infrastructure22 Interoperability Project  JISC Funded Interoperability Project  Prove the feasibility of delivering geo-spatial data using OGC standards for GIS web services within UK academia  The primary objective - develop a set of use case based demonstrator applications  promote interoperability between distributed data sources to maximize their combined value;  improve and enhance the communities experience of interacting with geospatial data; and  support the work of the Collections Team in developing further use of geospatial data resources already at the disposal of the community  Data centres involved MIMAS, EDINA, ICEDS & NERC
  • 23. 13th December 2006 Development Activities - Data Access Infrastructure23 Open Source Web Tools  MapServer 4.8.1  A freely available, open source development environment, offering support of WMS and WCS http://mapserver.gis.umn.edu/  Supporting libraries  PROJ 4 for on-the-fly projection  Geospatial Data Abstraction Library (GDAL) a translator library for raster data  Chameleon 2.0  Easily customisable web client for web service interface  Requires PHP MapScript module.  Many other web tools available e.g.  MapBender, kaMap, GeoServer
  • 24. 13th December 2006 Development Activities - Data Access Infrastructure24 Data Preparation  Pyramiding  25m, 50m and 100m resolution for ortholandsat 5 and 7 stretched mosaics.  Tiling  Shapefile index created for tiled data, improve server response time by requesting tiles that fall into the bounding box defined by the user.  Band Combinations  Landsat 5 mosaic bands 7,4,2 highlight urban areas in pinkish purple colour for the urban use case.  Create ECW and GeoTiff imagery in British National Grid  Required for image streaming and to provide as WCS
  • 25. 13th December 2006 Development Activities - Data Access Infrastructure25 WMS & WCS Configurationd Mapfile Structure Top of Mapfile Bottom of Mapfile Mapfile Elements Name, Extent, Shapepath, Imagecolour, Imagetype, Units, Debug Image path and ImageURL WMS title, onlineresource, accessconstraints, address, contactperson, contactorg, telephone, fees, keywordlist, abstract, srs EPSG code or Projection and Datum Name “png24”, Mimetype “image/png”, Driver “GD/PNG” Imagemode “RGBA” Extension “png” Name, group, status, type, tileindex, tileitem, offsite, transform, processing, debug, metadata and projection MAP WEB METADATA PROJECTION OUTPUTFORMAT LAYER
  • 26. 13th December 2006 Development Activities - Data Access Infrastructure26 MapFile - WMS Layer Element
  • 27. 13th December 2006 Development Activities - Data Access Infrastructure27 WMS GetCapabilities Request  GetCapabilities request  http://camber.mc.man.ac.uk/cgi-bin/mapserv.exe? map=wms_mimas_mosaic.map&REQUEST=GetCapabiliti es  Discover information about a WMS,  What layers are contained in the WMS,  Projection the data is being served in  Metadata information  Access constraints  Contact information
  • 28. 13th December 2006 Development Activities - Data Access Infrastructure28 MapFile WCS Configuration
  • 29. 13th December 2006 Development Activities - Data Access Infrastructure29 WCS GetCoverage Request  When using the below URL a download dialogue box will appear and will prompt the user to save the file. http://camber.mc.man.ac.uk/cgi-bin/mapserv.exe? map=wcs_mimas_mosaic.map&SERVICE=WCS&REQU EST=GetCoverage&Coverage=Landsat7Pan&BBOX=0, 0,700005,1050000&CRS=EPSG:27700&RESX=25&RE SY=25&FORMAT=ecw  The data can then be viewed and used in an image processing or GIS package e.g. ERDAS Imagine and ER Mapper.
  • 30. 13th December 2006 Development Activities - Data Access Infrastructure30 1. View & Download – Landmap OGC Client (WMS/WCS)
  • 31. 13th December 2006 Development Activities - Data Access Infrastructure31 Project Outcomes….Issues  Web services created are not secure therefore after the project services requiring authentication were withdrawn from interoperating  No infrastructure available as yet for authentication of users to OGC academic services  Require a modification to OGC web services to secure access to resources at the dataset level.  Clients created as part of the project did not provide any geo-processing capabilities or geographic analysis functionalities. Provides web mapping rather than web GIS  Cartographic quality  Require options for changing symbology of overlaid spatial data, creation of Style Layer Descriptors
  • 32. 13th December 2006 Development Activities - Data Access Infrastructure32 Web GIS Buffering Overlay operations Classification ICEDS Server EDINA Server OWS Providers Web Services WCS WMS WMS WMS WFS Web Client Output WCS Request Response MIMAS Server Graphs Maps Tables Download Software packages Metadata
  • 33. 13th December 2006 Development Activities - Data Access Infrastructure33 Benefits of Implementing OGC Services  Building relationships between institutions to achieve interoperability between web services sharing knowledge and expertise  Produce a range of OGC interoperable web services in academia (WMS;WFS;WCS) (MIMAS, UCL, EDINA and NERC)  Potentially enhances useful information that the end user can gain by combining a wide variety of data in one user interface Project Outcomes….Benefits 1
  • 34. 13th December 2006 Development Activities - Data Access Infrastructure34 Project Outcomes….Benefits 2  Investigate a range of web clients available to developers to serve WMS & WFS  Ionic Red Spider - ICEDS  Chameleon - MIMAS  RightWebMap - MIMAS  In-house built solution – EDINA  Economically cheap and fast to create OGC Services  Allowed the Satellite Image Data Service to provide an interactive mapping interface for users prior to downloading data
  • 35. 13th December 2006 Development Activities - Data Access Infrastructure35 Non Open Source Tools  ER Mappers Image Web Server  RightWebMap Client from ER Mapper Benefits  Real time zoom and roam capabilities using the Enhanced Wavelet Protocol  Cheaper price for academics  Easily configurable using the Image Web Server Console  Select the directories containing the data to serve  Provides a GetCapabilities request  Supports OGC WMS, ESRI ArcXML, Image X & ECWP  Can integrate a variety of WMS together to view data from different servers
  • 36. 13th December 2006 Development Activities - Data Access Infrastructure36 2. View – Landmap Image Streaming Client
  • 37. 13th December 2006 Development Activities - Data Access Infrastructure37 http://landmap.mimas.ac.uk
  • 38. 13th December 2006 Development Activities - Data Access Infrastructure38 3. View – Heavy Client e.g. ArcExplorer
  • 39. 13th December 2006 Development Activities - Data Access Infrastructure39 4. View & Download – Landmap Point & Click Area
  • 40. 13th December 2006 Development Activities - Data Access Infrastructure40
  • 41. 13th December 2006 Development Activities - Data Access Infrastructure41 Infrastructure Developments  3 Methods of Viewing  Web Mapping Service (WMS) via OGC Landmap Viewer  Image Streaming via Landmap Image Streaming Viewer OR via free downloadable heavy clients such as ESRI ArcExplorer or Cadcorp  Screenshots of the Data provided in Point & Click Download Service  2 Methods of Downloading Data  Landmap Point and Click (via drop down menus) service  Landmap Web Coverage Service (WCS) (still in development)
  • 42. 13th December 2006 Satellite Image Data Service 42 Learning Materials
  • 43. 13th December 2006 SIDS Learning Materials 43 New Image Processing Course Modules include: -Modules include: -  Information Extraction  Spectral Mapping  Geo-referencing  Structural Mapping  Vegetation Mapping  Land Cover Classification  Meteorology  Sea-Surface Temperature Mapping  Coastal Mapping  Integration with GIS  Mineral Exploitation Adapted for: -Adapted for: - RSI ENVIRSI ENVI ERDAS ImagineERDAS Imagine PCIPCI Idrisi KilimanjaroIdrisi Kilimanjaro Visit: -Visit: - www.landmap.ac.uk/ipcwww.landmap.ac.uk/ipc Requirements: -Requirements: - Athens Username &Athens Username & PasswordPassword Attend a subscribed institutionAttend a subscribed institution
  • 44. 13th December 2006 SIDS Learning Materials 44 Other Information Resources Include…  Canadian Centre for Remote Sensing Course  Geographical Information Systems Tutorial Provide Support  Advising users about available resources  Provide solutions and access to the latest datasets  Frequently Asked Question (FAQ) web pages  Support email to submit enquiries and requests  New ‘Image of the Month’ feature allows users to learn with examples
  • 45. 13th December 2006 Satellite Image Data Service 45 Future Work
  • 46. 13th December 2006 Future Work 46 Acquire New Data LiDAR sample data Licenses to be finalised with the suppliers Disaster Monitoring Constellation •Further ASAR Acquisitions
  • 47. 13th December 2006 Future Work 47 Future Work  Grid Enable the Satellite Image Data Service as part of the JISC approved GEMS II Project.  Create Metadata for the New ENVISAT ASAR data  Further develop the Interactive Mapping Service  Create further WMS and WCS  Incorporate the XML metadata into the Chameleon and RightWebMap clients  Explore the use of GloVis Java Heavy Client as a Catalogue Service  Create a Dynamic Map Extract tool for the Chameleon and RightWebMap clients
  • 48. 13th December 2006 Future Work 48 Microsoft IIS 6 response response request Front End Web Client Map Engine Web Server Storage Of Map Data WEB MAPPING SERVICE USER INTERFACE Cham / RWM PHP MapScript MAPSERVER WMS WCS MIMAS SAN request Mapfile Dynamic Map Extract request request
  • 49. 13th December 2006 Future Work 49 Proposal to JISC  1 - Extend the service for another five years  2 - Make the service free at the point of use, i.e. remove subscriptions to the service  3 - Enhance the service with yearly acquisitions of optical, (Landsat or equivalent like DMC) and radar images (twice a year for Envisat ASAR data)  4 - Develop a range of enhanced educational and support materials (e.g. exemplar use cases) http://www.jisc- collections.ac.uk/consultations/coll_consultations_existin g_renewal/coll_con_uksatelliteimagedata.aspx
  • 50. 13th December 2006 Satellite Image Data Service 50 Thanks for Listening  Enquiries: spatial@mimas.ac.uk Website: http://landmap.mimas.ac.uk