Evaluation of Geographic Information Standards

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Evaluation of Geographic Information Standards

• Mike Daniels
• Miner Miner

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Topics

• Recommendations
• Scaleable Vector Graphics
• ISO/TC 211
• Open GIS Consortium and Geography Markup Language

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Recommendations

• Utilize ISO 19125-1 Geographic Information
  Simple Feature Access
• A Simple Feature XML schema may be used to
  describe instance documents representing simple
  feature collections
• The XML payload upholds the principle of
  separating content from presentation - it does
  not address the visualization of encoded data
• A styling mechanism is required to display XML
  data on a particular device. For example, to
  display a map in a web browser you could
  transform the data into SVG (Scalable Vector
  Graphics) using an XSLT processor, and then view
  the resulting graphics with the Adobe SVG viewer.
• Pay close attention to evolution of the SVG and
  its support for GIS features
• Monitor the evolution of GML and its potential
  migration into the ISO 19125 standard

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Scaleable Vector Graphics

• SVG is a language for describing two-dimensional
  vector and mixed vector/raster graphics in XML
• W3C Recommendation 04 September 2001
• While recommendations are not international
  standards, many of the W3C recommendations become
  de-facto standards
• SVG is targeted as a standard feature on desktops
  (web browsers, graphical applications, authoring
  tools, file interchange), mobile and small
  devices (browsers, user interfaces, automotive
  systems), printers and industrial applications.
• Future goals To allow or include relevant
  enhancements from target domains such as
  GIS/Mapping, CAD/Design, Mobile, Printing and Web
  Design.
• Domain-specific enhancements may require the
  examination of SVG interoperability with another
  XML grammar

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Sample of Graphical Editing Tools That Export SVG

• Adobe Illustrator
• Beatware e-Picture
• CadStd Pro
• CorelDraw!
• SphinxSVG
• IsoDraw5

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SVG 1.1/1.2/2.0 Requirements

• SVG 2.0 requirements makes reference to the need
  for accommodating Coordinates and Transformations
  
• SVG should allow elements to be defined in the
  coordinate system used by the view port
• SVG 1.0 only allows elements to be defined in the
  user coordinate system, ensuring they are always
  affected by the current user space to view port
  transformation. Many applications, such as user
  interfaces, require objects that are not affected
  by the user space transformation, i.e. their
  position and size remain constant. Examples of
  such applications are the legend on a chart,
  symbols on a map and buttons in a user interface.
  SVG 1.2 SVG 2.0
• SVG should provide a mechanism to name the
  coordinate system used by sections of the
  document. For example, the coordinates used by
  the elements in the SVG file may be defined in
  the "D/WGS84" coordinate system. SVG 1.1 SVG
  1.2 SVG 2.0

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ISO/TC 211

• Standardization in the field of digital
  geographic information.
• This work aims to establish a structured set of
  standards for information concerning objects or
  phenomena that are directly or indirectly
  associated with a location relative to the Earth.
  
• These standards may specify, for geographic
  information, methods, tools and services for data
  management (including definition and
  description), acquiring, processing, analyzing,
  accessing, presenting and transferring such data
  in digital/electronic form between different
  users, systems and locations.
• The work shall link to appropriate standards for
  information technology and data where possible,
  and provide a framework for the development of
  sector-specific applications using geographic
  data.

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ISO 19125-1 Geographic Information Simple
Feature Access

• The OpenGIS Consortium (OGC) and the
  International Standards Organization (ISO) have
  adopted a common model for representing simple
  feature collections of geographic features.
• A Simple Feature XML schema may be used to
  describe instance documents representing these
  simple feature collections
• An XML instance document created under this
  schema can be validated for integrity, and
  provides an open, easily processed means of
  exchanging simple feature collections between
  systems.
• The Simple Feature XML encoding describes the
  structure of the geometry value in two forms
• As a Normalized XML schema
• As a Well-Known Binary Encoding based on the
  xsdbinary type

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Open GIS Consortium

• OGC is an international industry consortium of
  more than 220 companies, government agencies and
  universities participating in a consensus process
  to develop publicly available geoprocessing
  specifications
• The OpenGIS consortium has recognized the
  importance of XML as a mechanism for the exchange
  of schema and data

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GML

• The Geographical Markup Language (GML) attempts
  to define a standardized mechanism for the
  exchange of geographic features using domain
  dependent XML encoding guidelines
• A geographic feature is "an abstraction of a real
  world phenomenon it is a geographic feature if
  it is associated with a location relative to the
  Earth."
• GML has been designed to uphold the principle of
  separating content from presentation.
•  

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GML

• GML provides mechanisms for the encoding of
  geographic feature data without regard to how the
  data may be presented to a human reader
• Since GML is an XML application, it can be
  readily styled into a variety of presentation
  formats including vector and raster graphics,
  text, sound and voice.
• Generation of graphical output such as maps is
  one of the most common presentations of GML and
  this can be accomplished in a variety of ways
  including direct rendering by graphical applets
  or styling into an XML graphics technology (e.g.
  SVG SVG or X3D X3D).
• GML is not dependent on any particular XML
  graphical specification.

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Sources

• http//www.isotc211.org
• http//www.opengis.net/gml/01-029/GML2.html
• http//www.w3.org/Graphics/SVG/Overview.htm8
• Simple Features Specification, Keith Ryden