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1
Ports Pilot Services in XML/GMLEvolution of an
XML Schema for the Admiralty List of Radio
Signals, Volume 6

• For XML UK Member Presentation Day
• Peter Parslow (UKHO)
• James Rapaport (Atkins)

2
The book

• Ports, Pilots Vessel Traffic Services
• World coverage, in five parts
• Updated annually, with weekly bulletin of
  critical updates
• Legal requirement for commercial ships
• Maintained in QuickSilver

3
The Requirement

• Edit once, publish in various forms
• The book(s)
• An intelligent digital product
• The critical updates
• But we hadnt heard of XML (in 2001)

4
First Analysis

• Logical model
• S-57 objects attributes
• Trial parser
• Crystal reports
• List of issues
• Unicode 1!
• Formatting
• Document order
• Dates times
• Place names

5
First shot XML

• UML Diagram GML Like Schema
• .Net parser
• Proof of concept app.
• Little info on GML

6
First Shot XML (2)

• ltGEOGRAPHIC_AREAgt
• ltgmlnamegtANDAMAN ISLANDS (India)lt/gmlnamegt
• ltSERVICE_LOCATIONgt
• ltgmlnamegtPORT BLAIRlt/gmlnamegt
• ltgmllocationgt
• ltgmlPointgt
• ltgmlcoordinatesgt1141N 9247Elt/gmlcoordinate
  sgt
• lt/gmlPointgt
• lt/gmllocationgt
• ltMARINE_SERVICEgt
• ltgmlnamegtPilotslt/gmlnamegt
• ltCALL AUTHORITY"" CALL_SIGN"Pilot
  Station"/gt
• ltCONTACT TYPE"TELEPHONE" CONTACT_POINT""
  VALUE"91(0)3192 32834 amp 33691"/gt
• ltCONTACT TYPE"TELEGRAPH" CONTACT_POINT""
  VALUE"Harbour Master, Port Blair"/gt

7
Whats GML?

• Geography Markup Language
• Not just a way to express positions
• More a language for describing the world!
• Work in Japan Canada, merged by Open Geospatial
  Consortium, May 2000
• Becoming ISO 19136
• Features Properties (UML like)

8
GML Concepts

• Application Schemas
• Features
• Real world objects are modelled in GML as
  features
• But OS MasterMap (GML2.1.2) only eight types
  of feature

ltLightHouse gmlidLH1gt ... lt/LightHousegt
9
GML Concepts (2)

• Feature Properties
• XML alternating normal form
• Geometry in GML
• some properties encode the geometrical aspects of
  a feature a relationship to a geometry object

ltLightHouse gmlidLH1gt ltheightgt150lt/heightgt lt
positiongt ltgmlPointgt ltgmlposgt23.2
150.3lt/gmlposgt lt/gmlPointgt lt/positiongt ...
lt/LightHousegt

10
GML Concepts (3)

• Feature Relationships
• GML can describe relationships that may exist
  between features. For example
• Bridge feature crosses River feature
• River feature is crossed by Bridge feature

ltLightHouse gmlidLH1gt ... ltcontrolledFrom
xlinkhrefLHC1/gt lt/LightHousegt ltLightHouseCott
age gmlidLHC1gt lt/LightHouseCottagegt
11
GML in use

• Complex set of schemas 26! use a subset
• Data exchange
• Map View manipulation with GIS packages, or
  graphical view with SVG
• In the eGIF Technical Standards Catalogue
• GML 2.1 OS MasterMap local authorities
• GML 3.1 ISO 19136 International Hydrographic
  Orgn
• Wider ISO TC211 family web services, registries
• www.opengeospatial.org
• now, back to the plot

12
Revised Schema

• Studied GML XML best practice
• UML diagrams (Rose)
• UGAS tool XSLT from Rose XMI to XSD
• some editing mixed content, HTML-like tables
• Improved parser front end XSL on output

13
Revised XML (GML)

• ltalrsGeographicArea xmlnssmXML"http//metadata.
  dgiwg.org/smXML" xmlnsxlink"http//www.w3.org/19
  99/xlink" xmlnsalrs"http//www.ukho.gov.uk/schem
  a/alrs_vol_6" xmlnsgml"http//www.opengis.net/gm
  l" xmlnsxsi"http//www.w3.org/2001/XMLSchema-ins
  tance" xsischemaLocation"http//www.ukho.gov.uk/
  schema/alrs_vol_6 ..\Schema\alrs_vol_6.xsd"gt
• ltgmlnamegtANDAMAN ISLANDS (India)lt/gmlnamegt
• ltalrsserviceLocationMembergt
• ltalrsServiceLocation gmlid"PORTBLAIR"gt
• ltgmlnamegtPORT BLAIRlt/gmlnamegt
• ltalrspositiongt
• ltgmlPointgt
• ltgmlposgt11.68 92.78lt/gmlposgt
• lt/gmlPointgt
• lt/alrspositiongt
• ltalrsmarineServiceMembergt
• ltalrsMarineServicegt
• ltalrsserviceNamegtPilotslt/alrsserviceName
  gt
• ltalrscontactInformationgt
• ltalrsContactgt
• ltalrscontactPoint/gt
• ltalrscontactDetailsgt
• ltsmXMLCI_Contactgt
• ltsmXMLphonegt

14
Choice of tools 0

• Corel XMetal Author 4 poor XSD support
• Xopus doesnt support abstract elements
• OpenOffice.org 1.1 uses own schema
• MS Word 2003 Professional converts to own
  schema
• Altova XMLSpy 2004 crashes if you move/delete
  chunks
• Altova Authentic also crashes

15
Altova views
Authentic view input
Browser view - proofing
16
Data conversion

• Data conversion
• Analysis prototyping year?
• Custom parser - 50 days?
• Tidy the QuickSilver files - 12 days?
• 100 manual checking of the XML (styled to HTML)
  60 days
• semi-automated checking (style sheets which
  highlight errors) 20 days
• Cleansing / correction - 150 days
• Training
• UML training for senior users
• XML / GML training for editors

17
Where now?

• Contracts let to build database product
• GML as exchange format
• GML to pre-press file (PDF) for paper books
• Could go on
• Metadata
• Coordinate reference systems
• Statements of quality

18
Was it worth it?

• Jury still out
• XML good
• GML good
• Tools not much good
• Data conversion expensive
• But no more expensive than any other port?
• Wed built another XML flow line between slides 4
  5!

19
Finally

• Thanks to
• Technical editorial colleagues
• XML UK,
• and you for listening
• Peter.Parslow_at_ukho.gov.uk
• www.ukho.gov.uk/UKHOTechnicalForum/forums
• www.opengeospatial.org