Enterprise Centerline Data

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Enterprise Centerline Data Metro Nashville
Public Works

• Mr. Donald Reid,
• Paving and ROW Operations Manager,
• Metro Nashville Public Works
• donald.reid_at_nashville.gov
• Jeff Deason,
• GIS IT Services Manager,
• Collier Engineering Co., Inc.
• jeff.deason_at_collierengineering.com

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Our Presentation Covers 3 Main Topics

• The Enterprise-wide Availability of GIS Data
  Representing the Metro Nashville Davidson
  County Roadway Network.
• The Use of Centerline (CL) Data within the Metro
  Public Works Long-Term Pavement Preservation
  Program Across MPW.
• The Relationship Between These MPW Programs the
  Continual Improvement of the Enterprise Dataset.

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The Enterprise-wide Availability of GIS Data
Representing the Metro Nashville Davidson
County Roadway Network

• Access and stewardship of the enterprise CL data
  resource in the Metropolitan Government of
  Nashville Davidson County is distributed among
  several departments for multiple uses.
• Distributed access to the live CL data is
  provided through ESRI ArcSDE from the Metro
  Nashville Planning Department.
• Good communication between departments results in
  workable access agreements and fosters continual
  improvement to the usefulness and accuracy of the
  street data.

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CL Data Access Options

• Metro employees can access the live CLs by
  connecting to a geodatabase feature class being
  served through ESRI ArcSDE in Metro Planning.
• Employees can refer to the Planning section of
  the nashville.gov web site for search, view, pan,
  zoom.
• Employees can work with shapefile or personal
  geodatabase snapshots of the live street data,
  if required.

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Live CL Access Through Plannings Geodatabase

• Up Side Most Accurate Reference
• Down Sides
• Multiple Potential Choke Points
• Must establish login password
• Auto-expiring passwords
• Dependent on performance of the RDBMS
• Dependent on performance of all network
  connections between the RDBMS and the users
  computer
• A closed dataset
• Edits generally limited to the E-911 Coordinator
• Cant be accessed directly by 3rd-party apps

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Centerline Access via the Nashville.gov Web

• Good for view-only access
• No real analysis other than visual.
• Site geared to find parcel data and other
  resources based on address, not specifically to
  query/find street data.
• Google Maps or HandyMap may be just as useful,
  and more user-friendly for orientation and
  connectivity issues, etc.

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Centerline Snapshots of the Live CL Data

• Shapefiles or personal geodatabase feature
  classes extracted from the enterprise CL dataset.
• More suitable for use with 3rd-party apps, but
  disconnected from the enterprise resource.
• Edits made to snapshot may be useful for
  enterprise, but getting that back into the
  enterprise geodatabase requires careful planning
  and communication between departments.

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Metro Nashville CL Data Product of Multiple
Sources Processes

• Some of the linework has been
• Digitized from old Mylar/paper parcel maps
• Derived from plans provided by developers
• Hand-digitized from orthophotography or from ROW
  polygons
• Imported from CAD data

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Metro Nashville CL Data Product of Multiple
Sources Processes

• Some of the data attribute values have been
• Bulk-loaded from other systems or projects as
  needed/available
• Hand-edited by consultants and staff in multiple
  departments
• Structurally re-defined as part of a recent RDBMS
  migration

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Metro Nashville CL Data Structure Attributes

• Segmentation terminates at nodes
• Intersections with other streets
• Bridges
• Satellite City boundaries
• County boundaries

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Metro Nashville CL Data Structure Attributes

• Naming
• PREFIX_DIR (N, S, E, W)
• NAME
• SUFFIX_TYPE (DR, AVE, BLVD, PIKE, etc.)
• SUFFIX_DIR (N, S, E, W)
• FULL_NAME (combine previous 4 fields)
• ALT_NAME
• FORMER_NAME

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Metro Nashville CL Data Structure Attributes

• Connectivity
• FROM_STREET (intersecting street at segments
  lowest address point)
• TO_STREET (intersecting street at segments
  highest address point)
• NAVIGABLE (related to OFFICIAL_STATUS and
  LEGISLATION)

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Metro Nashville CL Data Structure Attributes

• Addressing
• LEFT_FROM (lowest address value possible on the
  left side of this segment)
• LEFT_TO (highest address value possible on the
  left side of this segment)
• RIGHT_FROM (lowest address value possible on the
  right side of this segment)
• RIGHT_TO (highest address value possible on the
  right side of this segment)

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Metro Nashville CL Data Structure Attributes

• Accepted Status
• Accepted Adopted and maintained by Metro
  Nashville Davidson County
• Accepted State Aid segments are maintained by
  Metro Nashville with State funding
• Not Accepted State or Other Government /
  Satellite Cities
• Not Accepted Private Roads/Drives
• Not Accepted Under Development

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Metro Nashville CL Data Structure Attributes

• Legislative Acts
• Acceptance Date
• Streets in new subdivisions may take years before
  acceptance, depending on several variables
• Accepted streets in newly annexed areas would
  likely all have the same acceptance date.
• Abandonment Date
• Existing, but no longer maintained.
• No longer existing due to development
• Either way, its a historic line now.
• Naming Changes

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Metro Nashville CL Data Structure Attributes

• Other Fields Available
• Many other (UNETRANS) fields available.
• Some are populated and maintained.
• Some have been partially populated for studies or
  short-term projects, but not maintained.
• Others are there for future use, but have never
  been populated due to minimized need.

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CL Data is the Basis for Several Processes within
Public Works

• Customer Service Department ArcView Cityworks
• CL snapshot due to connection concerns vs
  always-on nature of customer service.
• Reps geocode incoming SR calls in real-time
• Manual geocoding tools help reps to deal with SR
  incident addresses that dont automatically
  geocode.
• Cross-departmental communication ensures E-911
  Coordinator knows to analyze segments w/
  geocoding issues.

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CL Data is the Basis for Several Processes within
Public Works

• Customer service reps can immediately close some
  service requests through simple geocoding.
• When is trash-pickup day for my street?
• When will my street be paved?
• When will the alley behind my house be cleaned?

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CL Data is the Basis for Several Processes within
Public Works

• Other SRs are assigned by type and priority to
  inspectors, who benefit from the CL data and
  geocoded SR data.
• Immediate map-based identification of active
  service requests by type and status and work
  sector.
• Inspectors benefit from visual clustering of
  active inspection workload to assist in simple
  route planning.
• Pattern recognition reporting over time.

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CL Data is the Basis for Several Processes within
Public Works

• Maps and reports to enhance communication with
  Finance, Metro Council, other departments, and
  public citizens via 311 or Nashville.gov web
  site.
• Paving Plan Maps
• Weekly Work Coordination Maps
• Trash Recycling Route Maps
• Snow Route Maps
• ROW Maintenance Schedules
• Closure Notifications
• Bulk Item Pick-up Requests
• Dead Animal Reports
• Traffic Calming

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CL Data Usage within the Paving Operations Office

• Pavement Management workflow and maintenance
  decisions are supported by
• Physical inspections annual photo and distress
  data collection
• Customer Service requests and other forms of
  public input
• Photo log custom ArcGIS Roadway Viewer
• Cartegraph PavementView for ArcGIS

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Annual Roadway Data Collection in Support of
Paving Operations

• 4 photos shot every 20 (front, front-right,
  rear-left, rear-down)
• Laser distress analysis to help gauge roughness
  and raveling .

• Process develops overall condition index (OCI)
  for use in Pavement Management system.

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CL Data Usage within the Paving Operations Office

• While several of these projects use CL data
  snapshots, some data elements from these
  projects would be of benefit to the enterprise
  users, so careful process management ensures that
  the appropriate aspects of locally-altered
  segment data are reflected back to the enterprise
  geodatabase at appropriate intervals.

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CL Data Usage within the Paving Operations Office

• Example Last-paved Date
• This field is updated in PavementView then pushed
  over the enterprise CL geodatabase.
• From there it is imported into the enterprise
  Permitting system (KIVA), where it serves to
  trigger additional fees for applicants who apply
  for permits to perform pavement cuts on recently
  resurfaced roadways.

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Collected Data Helps Calculate OCI

• OCI values, threshold trigger values, and annual
  program funding levels influence CarteGraph
  PavementView to make suggestions toward decisions
  on scheduling treatment
• Resurfacing (mill fill)
• Rejuvenation
• Crack seal
• Alternate treatment
• Wait

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TRANSPORTEDGEID is the Key to the Use of CL Data
Snapshots

• TRANSPORTEDGEID is the Primary Key. However,
  when a segment is split (new intersection
  created), it results in a new TRANSPORTEDGEID
  value for each of the resulting children. The
  original parent segment (and ID) is retired and
  copied to an archival layer.
• This means special care must be taken to ensure
  that appropriate data transfer occurs in the
  event that segmentation changes while
  Paving-related GIS/IT projects are working with a
  snapshot of the same area.

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Continued Data Improvement Through Distributed
Access

• As with the use of Cityworks and RouteSmart, the
  programs in Paving Operations sometimes uncover
  CL data errors (network connectivity, addressing,
  TO/FROM naming, accepted status, etc.), which are
  then forwarded to the E-911 Coordinator for
  review/approval.
• Such incremental improvement is another way in
  which the use of data snapshots usually strongly
  advised against if enterprise data access is
  available has proven beneficial to the
  enterprise as a whole.

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Conclusions

• Metro Nashville Davidson County provides
  several means for its staff and consultants and
  citizens to access roadway centerline data.
• Real-time street CL data is available as a
  geodatabase feature class served through ESRI
  ArcSDE, but can be overkill for some projects and
  not enough for others.
• Some internal projects require direct access to
  analyze and edit a standalone snapshot of the CL
  dataset.
• Managed carefully, the use of snapshots can
  ultimately add value to the enterprise CL
  dataset.