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Web Map Services provided by the Map Supply in Denmark

Web Map Services provided by the Map Supply in Denmark. Skånekartan workshop. Nikolaj Kamstrup, Kort & Matrikelstyrelsen, Denmark. 7-11-2005. Who am I?. Nikolaj Kamstrup Cand. scient (Physical Geography) – master thesis in remote sensing

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Web Map Services provided by the Map Supply in Denmark

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  1. Web Map Services provided by the Map Supply in Denmark Skånekartan workshop Nikolaj Kamstrup, Kort & Matrikelstyrelsen, Denmark 7-11-2005

  2. Who am I? • Nikolaj Kamstrup • Cand. scient (Physical Geography) – master thesis in remote sensing • Involved in the development of the Map Supply from the beginning in 2001 • Employed in Kort & Matrikelstyrelsen October 2003 • Head of the Map Supply product development team that currently counts approximately four full-time persons • Member of the OGC Technical Committee

  3. Agenda • What is the Map Supply – a brief overview • Overview of geodata accessible through the Map Supply • Basic WMS • Extended WMS • Gateway description • Styled Layer Descriptor and Filter Encoding support • Questions

  4. The Map Supply • The Map Supply is the name of a wide range of web services based on geo data from Kort & Matrikelstyrelsen • Presented as a prototype November 2001 • The purpose is to: • Live up to the geodata infrastructure provider role as defined by the current government • Ensure that our up-to-date geodata can be accessed through the Internet from all applications at all times • Decrease the need for fixed media geodata deliveries e.g. DVD and CD-ROM • An extensive partner program is a part of the Map Supply (currently more than 20 partners)

  5. WMS • Web Map Service – raster images and object information • Extended with image manipulation functionality e.g. grey scale, sharpen, contrast and distortion options • Supports user styling (SLD) and filtering (Filter Encoding) GEO • Search tool for place names, addresses, land registrations and other spatial objects as administrative boundaries • Coordinate transformation META • Nice-to-have functionalities e.g. real-time statistics and user rights information Print • Web Map Service optimised to large extents • Cartography adjusted to printing purposes rather than screen display WFS • Web Feature Service – object information in GML • Supports filtering • Not implemented yet Current Web Services provided by the Map Supply

  6. WMS GEO WFS Print META The Map Supply Gateway The Map Supply Application Geodata

  7. The Map Supply Consumption

  8. Statistik – fordeling af forespørgsler

  9. Topograchical - Overview (< 1:500.000) - Detailed (> 1:100.000) - Traffical/road - Administrative areas X X X Ortofoto Historical X X Data content of the the Map Supply WMS Data category Raster Vector Cadastral X X X X X

  10. Demo

  11. Extension of WMS functionality • The Map Supply has added further functionality to the WMS including: • On-the-fly image manipulation e.g. greyscaling and sharpening • Advanced exception handling  ignore exception and exception descriptions in Danish • Support for several GIS clients (ArcMap, MapInfo) to deal with the fact that access to the Map Supply WMS’s require authentification (login) • Extensions are implemented as one or more URL parameters • All extensions are implemented on a central level (in the gateway) rather than on an application server level  resistant to changes in WMS software

  12. Enhancement of WMS specification (VendorSpecificCapabilities) Additional functionality/enhancement is described in the GetCapabilities response

  13. Manipulation example

  14. Convolution examples Regular Light Blur Sharp

  15. Gateway description • Originally developed to obtain a single point of contact (gateway) • Today it has developed into a rather ”intelligent” gateway including: • Load balancing • Authentication and authorisation (WMS spec does not deal with this topic) • Selfdefense management (maintained centrally rather than on the application server level) • Correction of lack of WMS compliance (do not trust the OGC compliance logo) • WMS enhancement e.g. image and XML manipulation (greyscaling, similar XML encoding for all WMS) • Logging for several purposes e.g. billing and error corrections

  16. Log Login handler Get URL parameters Find service Execute self defense Verify user rights Wait for access Find WS provider Analyse response Gateway internal data flow SM Policy Server Internet Map Supply Gateway Request User directory Response Is the result OK? If not, should any messages be returned in Danish or English? Verify XML encoding in response. If encoding is not ISO-8859-1 it will be transformed SiteMinder Web Agent User rights Used for statistics, accounting and error corrections Is the user is known by the Map Supply? Geodata • Verify that the request is complete • Verify that parameter values are valid e.g: • Is SRS parameter valid? • Can the BBOX be parsed? • Is LAYERS parameter valid? • Is FORMAT parameter valid? • Are all layers valid in combination with the requested extent given by BBOX? • Verify that the user has the right to make this request e.g.: • Does the user have access to the service and/or layers? • Is the requested BBOX within the extent allowed for the user? Web Services providers WMS and WFS Request WS provider

  17. GEO v1 (ASP) GEO v2 (.Net) WMS (ArcIMS) Print (ArcIMS) WMS (Ionic RSW) WFS (Ionic RSW) Load balancing in the Map Supply Gateway kmsload1 kmsload2 kmsload3 kmsload4 kmsload5 kmsload6 kmsload7 kmsload8 At least two application servers per web service

  18. WMS 1 WMS 5 WMS 4 WMS 3 WMS 2 Added user rights personalise/constraint WMS Personalised WMS: - Layers - Extent/area - Image size - Attribute queryable One WMS  easy maintenance User rights WMS User rights can be set/changed by the user himself through a web interface

  19. Demo

  20. Yes Filter Encoding No Named User Styles Development directions of WMS in the Map Supply Possible to define style for one or several objects in a given layers WMS+SLD+FE WMS+SLD WMS Possible to define style for all objects in a given layers Basic WMS – one style per layer. Styles defined by provider.

  21. Illustration of the evolution in WMS WMS WMS+SLD WMS+SLD+FE

  22. Example of WMS and Styled Layer Descriptor Cadastral map including a few topographic themes e.g. lakes and buildings. The ground control points (fikspunkt) are highlighted with a dark red color link

  23. Example of WMS and Filter Encoding All land parcels are styled according to their area (an attribute of the object). Five area intervals are establis-hed with a red style for the smallest and an off-white style for the largest ones. link

  24. Demo

  25. Questions • Shoot!

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