OGC

1
OGC

• Web Mapping Testbed
• September 1999

2
OGC Participation

• First contacted the OGC in connection with SAIF
  Geomate in 1993 first meeting in 1994.
• Very active participant (information communities,
  spatial reference systems) until 1996.
• Rejoined as Galdos Systems in 1998
• Created and led the Xbed team to pursue XML
  technologies for WWW based spatial data handling.
• Author of RFC for Geographic Markup Language
  (GML)
• Host of OGC Meeting, Vancouver Feb 7-11, 2000.

3
What is the WMT ?

• Ongoing, evolving platform for the development
  evaluation of global geo-spatial information
  standards.
• No net but the net.
• Launched with WMT IOC project April 1999 - first
  public demonstration, September 10, 1999.

4
Xbed Technology Demonstrations

• Ron Lake,
• President, Galdos Systems Inc
• rlake_at_galdosinc.com

5

• Xbed Team

• CubeWerx
• Compusult
• Galdos Systems Inc
• MapInfo
• NTT Data
• Oracle
• PCI Geomatics
• Sun Micro Systems

6
Current Web Technology

• Http requests to web servers with CGI, or to
  servlets.
• Browsers display only GIF,JPEG or PNG
• Suited to display of maps only!
• Limited interactivity - no standard vectors
• hard to link to feature properties
• cant separate content presentation
• Whats next ?

7
XML Technologies

• Provides text encoding of all data.
• Uses a Document Type Definition or Schema to
  ensure document/data consistency.
• XML technologies are becoming widely used on the
  World Wide Web. Over 100 XML derived languages in
  last year!

8
XML Encoding of Geography

• Encodes geometry of geographic features
• Encodes property lists (feature attributes)
• Encodes spatial reference systems
• Encodes geographic functions (coverages)

9
An XML Geo-Data Server
Client Program
Spatial Data Request
Geographic data encoded in XML
Persistant Store (XML or Non-XML)
demo
10
Drawing a Map
Converts geographic data into graphic elements!
Client Program with Map Rendering Engine
Map Style Sheet
Spatial Data Request
Geographic data encoded in XML GML
Persistent Store (XML or Non-XML)
NTT demo
11
More XML Technologies

• XSLT - A transformation language for XML
• SVG - Scalable Vector Graphics - an XML encoding
  of graphics for 2D drawing
• VML - Vector Markup Language - another XML
  encoding of graphics for 2D drawing
• These are moving to be W3C Standards !!

W3C World Wide Web Consortium
12
Using XSL and SVG
SVG Plug-in or Active-X Control
XSLT Style Sheet
SVG
XSLT Engine
XML Parser
GML Data
Standard Web Browser
Galdos demo 1
13
(No Transcript)
14
Separation of Presentation and Content
ltFeature fid"1" featureType"pond"gt
ltDescriptiongtsmall pondlt/Descriptiongt ltPolygon
GeometryID"2" SRS_Name4336" NumRings"1"gt
ltLRinggt ltCList dimension"2"gt0.6,1.5 0.5,0.5
1.0,0.7 1.5,1.5lt/CListgt lt/LRinggt
lt/Polygongt lt/Featuregt
XSLT, or other Style Engine
Geographic data
a map
Style Sheet
15
Same Data - Different Styles
XSLT Style Sheet 1
XSLT Style Sheet 2
XSLT Engine
XSLT Engine
SVG
SVG
XML Parser
XML Parser
USGS
US Army
GML Data
16
Inside an XSL Map Style Sheet
Find the geographic features
ltxslapply-templates select"//Feature_at_featureTy
pe'rP4D'/Lstring /gt ltxslapply-templates
select"//Feature_at_featureType'nursery'/Polygon"
/gt ltxslapply-templates select"//Feature_at_featur
eType'river'/LString /gt
Style as graphics (SVG)
ltxsltemplate match"Feature_at_featureType'marsh'
/Polygon"gt ltxslelement name"path"gt
ltxslattribute name"style"gtfillaqualt/xslattr
ibutegt ltxslattribute name"id"gtltxslvalue
-of select"ancestor(.)/_at_featureType"
/gt-ltxslvalue-of
select"ancestor(.)/_at_fid"
/gtlt/xslattributegt ltxslattribute
name"d"gtltxsleval language"VBScript"gtConvertCLis
tToVerts(me.text)lt/xslevalgtlt/xslattributegt
lt/xslelementgt lt/xsltemplategt
17
Easy client side drill down
ltFeature fid"1" featureType"pond"gt
ltDescriptiongtsmall pondlt/Descriptiongt ltPolygon
GeometryID"2" SRS_Name4336" NumRings"1"gt
ltLRinggt ltCList dimension"2"gt0.6,1.5 0.5,0.5
1.0,0.7 1.5,1.5lt/CListgt lt/LRinggt
lt/Polygongt lt/Featuregt
XSLT, or other Style Engine
Geographic data
a map
Style Sheet
Client side access to geographic data
Galdos demo 2
18
Easy Client Side Interaction
ltFeature fid"1" featureType"pond"gt
ltDescriptiongtsmall pondlt/Descriptiongt ltPolygon
GeometryID"2" SRS_Name4336" NumRings"1"gt
ltLRinggt ltCList dimension"2"gt0.6,1.5 0.5,0.5
1.0,0.7 1.5,1.5lt/CListgt lt/LRinggt
lt/Polygongt lt/Featuregt
XSLT, or other Style Engine
Geographic data
a map
Style Sheet
Easy Client Side Feature Selection and Hi-Lighting
Galdos demo 2
19
Easy Client Side Drawing
Map Viewer
Map Editor
Illustration of client side drawing and update
NTT demo 2
20
Client or Server
Galdos demo 3
Client
Client
XSLT Style Sheet 1
XSLT Engine
SVG
XML Parser
SVG
XSLT Style Sheet 1
XML Simple features
XML Simple features
XML Parser
XSLT Engine
Server
Illustration showing Map Styler running on Server
or the Client
21
Flexible Data Transformation
Requestor (client)
Data Source and Transform Request
Transformed XML
XSLT Servlet
XML
XSLT Sheet
XML Data Store
Illustration of XSLT Engine Enabled Transformation
22
Flexible Data Transformation
Requestor (client)
Data Source and Transform Request
Transformed XML
XSLT Servlet
XML
Coordinate Transformation XSLT Sheet
XML Data Store
Illustration of XSLT Engine Enabled Transformation
23
Coordinate Transformation
Washington
Map is rendered on client from geographic data
Request (XML Source, XSL Transformation)
XML encoded Simple Features
XML Data Source
XSLT Style Sheet
Coordinate Transformation Service
GetMap
Ottawa
Vancouver
Illustration of XSLT Coordinate Transformation
Service
Galdos demo 4
24
Managing Dynamic Information
Current state of the situation
Name ...
Other situation objects this object contains!
Status .. Contents .. Creation
. Termination . StatusHistory .
Link to external objects/data
Creation Time/Date
E.g. database records for bridges, roads, levees
etc.
Termination Time/Date
E.g. Situation Object for Red River Flood
StateHistory
RDF can be used to manage dynamic meta-data
25
Summary

• XML Technologies offer real potential to
  significantly impact geo-spatial data and systems
  interoperability on the Web.

26
Impact of the WMT

• Led to development of GML RFC
• Led to important relationships with major vendors
  and sponsors.
• Basis of our current work on developing GML
  Technology

27
Future Work

• Geographic Markup Language (GML) Technology
• Tools for map making with SVG
• Coordinate Transformation Service(s)
• XSLT Extension Function for spatial analysis
• XLink/XPointer implementations
• GML Spatial Database(s)
• GML Conversion utilities (SAIF ? GML, Shape ?
  GML)
• Coverage extensions to GML
• Topology extensions to GML
• GML performance issues

28
Lessons

• Participation in the OGC is very valuable
• Link to many companies and organizations
  throughout the world
• WMT approach is to evaluate/build/test
• key to fast tracking workable standards in Web
  time.

29
Questions Please!