TOPOGRAPHIC DATA RESTRUCTURING

1

• TOPOGRAPHIC DATA RESTRUCTURING
• The bridge between CAD and GIS
• Marty Stamatis
• Manager, Topographic Restructure Project
• 09 February 2005

2
Presentation Outline

• Background
• Benefits
• User Requirements
• The Environment
• Data Modelling

• System Development
• Topology
• Data Migration
• Data Issues
• Maintenance Issues

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Typical Topographic Data
4
Background

• History
• The Department of Lands and Surveys was the main
  source for base topographic data. The Army and
  National Mapping also played a significant role
  in mapping the state.
• Output hard copy but moved to digital in the
  early 1980s
• Other state government agencies now hold their
  own copy of the digital topographic data.
• Committees
• Intergovernmental Committee on Surveying and
  Mapping (ICSM) Topographic Working Group
  (National Topographic Data Model) Harmonised
  Data Model (Cadastral, Topographic, Place Names,
  Property Street Address)
• ICSM Permanent Committee on Topographic
  Information
• Topographic User Surveys
• DLI initiated Topographic Data Workshop - July
  2001
• DLI initiated Independent User Survey - March
  2002
• WALIS surveys conducted after 2002
• Topographic Enhancement Project (TEP)
• Precursor to the TOPOGRAPHIC RESTRUCTURE PROJECT
  (TRP)
• Test the feasibility of restructuring the
  topographic data and subsequently develop a case
  for the migration of the whole dataset into a new
  agreed environment
• Commenced in August 2002, ended in July 2003
• TOPOGRAPHIC RESTRUCTURE PROJECT began in November
  2003 (2 yr project)

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Benefits

• Customer Benefits
• DLIs commitment to fundamental data
• Provision of a definitive topographic GIS dataset
• Minimises the need for post processing the data
• Provision of a rigorous dataset (through the use
  of topology)
• Provision of a mechanism for taking incremental
  updates rather than full data downloads
• Provision of a mechanism for linking customers
  attributes to the spatial data
• Agency (DLI) Benefits
• Moves the data from a CAD to a GIS format
• Rationalisation of the maintenance task within
  the agency
• Improves access to the data
• Aligns maintenance systems
• Partnering with other agencies to share the data
  maintenance load
• Keeps abreast with changing technology
• Cost Benefit
• Relatively small return on investment
• Community Service Obligation

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User Requirements

• Formation of a User Reference Group
• WALIS Councillors were asked to nominate
  representatives
• 20 member user reference group formed comprising
  representatives from
• WALIS Advisory Committee
• 15 Government agencies
• Local Government
• Private sector (2)
• Role of the User Reference Group
• To provide a customer focus
• Identify
• Required functionality
• The data to be included
• Potential partnering opportunities for data
  maintenance
• Review
• The data model
• The prototype GIS dataset

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The Environment

• Choice of Environment
• ESRI Environment
• Customer survey outcome
• Geodatabase (ESRI direction)
• Topology - the spatial relationships between
  geographic features fundamental to ensuring
  data quality
• Proven environment (opportunity to share
  knowledge/experience with other states to fast
  track design/development)
• Out of the box rather than custom built
• Client Software
• ArcGIS 9 (ArcEditor license level)
• PLTS/JTX extensions (Production Line Tool Set and
  Job Tracker)
• Corporate Enterprise Database
• Maintenance Environment
• Unix environment
• ArcSDE 9
• ORACLE 9i
• Project Team

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Data Modelling

• Data Modellers Brief
• Topographic vector data 125,000 1100,000
• Relief, Hydrography, Roads, Railways, Cultural,
  Utilities, limited Vegetation, Named Features
• 2 dimensional
• Excludes Digital Elevation Models (Grids and
  TINs)
• ICSM Harmonised Data model compliant
• Environment Scan
• Data Dictionary
• Seamless Database
• Incremental Update
• Name Attribute (Geographic Names Register
  identifier GEONOMA)
• Persistent Identifier (Foreign Key)
• Feature Level metadata
• Balance Analysis and Map Publishing
• MUST BE SUSTAINABLE
• Data Modelling Process
• CASE Tool Visio Professional 2002
• Feature Classes (45), Sub Types (103), Domain
  Tables (83)

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Data Modelling
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System Development

• Database Building
• Add low level ORACLE triggers to manage the
  required functionality (incremental update,
  persistent identifiers)
• Management of retired/deleted features
• Setup of scripts to manage the environment
• Editing Tools
• Metadata assignment interface
• GEONOMA (feature name) assignment interface
• Customised tools to aid editing (moving/copying
  features between feature classes / subtypes,
  customised tool sets)
• Defining symbolisation
• Quality Assurance
• Topology Rules
• Condition Tables within the database (PLTS
  functionality)
• A variety of scripts to test the integrity of the
  data (tracing tools based on common attributes,
  contour height checks, minimum length, minimum
  area, valid name, etc.)

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Topology Rules

• What is Topology?
• Topology is a set of integrity rules that define
  the behavior of geographic features (how features
  share geometry). Topology is fundamental to
  ensuring data quality.
• In the ArcInfo "coverage" model, topology was
  created using the build and clean operations. In
  ArcGIS 8.3 and above we have user-defined
  topological relationships with a Geodatabase.
• 53 topology rules in the data model

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Topology Integrity
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Data Migration

• Data
• Themes
• Cultural (includes industrial and utilities type
  features)
• Hydrography
• Ground Surface (contours and physiographic
  landform features)
• Transport (road and rail)

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Data Migration

• Seamless Blocks
• Data is grouped into blocks based on its metadata
• Data within blocks is made physically seamless
  (no pseudo nodes)
• Approximately 150 blocks per theme
• Block to block data is logically seamless (has
  pseudo nodes)

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Data Issues

• Data Cleansing prior to loading into the GIS
• The CAD data is being cleansed of spatial and
  attribute problems prior to its migration to the
  GIS environment.
• The software used to detect and cleanse the
  anomalies includes MicroStation, Enforcer,
  Polygon Processor, ArcGIS, and Safe Softwares
  Feature Manipulation Engine (FME).

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Data Issues
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Maintenance Issues

• State Land Information Capture Program (SLICP)
• Coordinated capture program produced with input
  from all WALIS stakeholder agencies, other State
  government agencies and local councils in WA. The
  program co-ordinates data capture by prioritising
  agency requirements and determining areas of
  greatest whole of government" need.
• Topographic information capture can be either
• New
• Total map sheet replacement
• Changes only
• Investigating possibility of re-aligning the
  aerial photography revision program to provide
  better source information for data maintenance
• Alignment with thematic map revision (street
  directory, travellers atlas, country towns
  touring maps)
• Partnering
• Whole of Government approach to the maintenance
  of data rather than a map revision mentality
• Utility Data
• Railways
• Points of Interest
• Hydrography
• Roads
• Medium to long-term goal is to have agencies
  physically maintain the data

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Contact Details

• Marty Stamatis
• Postal Address Department of Land Information
• 1 Midland Square MIDLAND 6056
• Phone Number [phone]
• E-mail marty.stamatis_at_dli.wa.gov.a
  u