Montana Department of Transportation (MDT) Location/Linear Referencing System (LLRS) Design Process

Transcription

1 Montana Department of Transportation (MDT) Location/Linear Referencing System (LLRS) Design Process Marlin Sander, MDT and Bill Schuman, GeoDecisions

2 Session Outline Current MDT s transportation inventory system environment Goals for updating MDT s Location/Linear Referencing System (LLRS) environment LLRS design process Conceptual and logical design results Future direction Questions

3 MDT Transportation Inventory Environment Basic System Architecture Transportation Information System (TIS) Evolved from the mainframe Highway Information System (HIS) in 1997 Oracle relational database environment Contains a combination of the LRS and related attributes in one system Not directly linked to a 3-D spatial location Roadlog base Uniformly attributed segments derived from dynamically segmentation of TIS records End-user view of data

4 MDT Transportation Inventory Environment Route/Corridor Definitions Base Route Control segment linear referencing method Naming/assigned route number Letter/number naming process (S00229, U05809, I00090) Historically route number was meaningful Currently route number is unintelligent Problem no way to keep history of route distances and associated business data Problem continued using the historical name/numbers and users still think of that value as meaningful

5 MDT Transportation Inventory Environment Base Route Example Lyndale Ave 0 Secondary / Urban Interface (Historical) Urban Boundary 5.13 S00229 Lincoln Rd U Lyndale Ave 0 Urban Boundary 5.38 S00229 Lincoln Rd U

6 MDT Transportation Inventory Environment Route/Corridor Definitions Corridor Route More closely reflects the traversal of a full named route Less dependent on changes in route alignments or lengths Allowed more consistency over time Problem still not intuitive to field data collection personnel ( values resembled base routes )

7 MDT Transportation Inventory Environment Corridor Route Example Lyndale Ave Secondary / Urban Interface (Currently) U05809 Urban Boundary S00229 Lincoln Rd 0 C Lyndale Ave U05809 Urban Boundary (New) S00229 Lincoln Rd 0 C

8 MDT Transportation Inventory Environment Corridor Route Example

9 MDT Transportation Inventory Environment Route/Corridor Definitions Departmental Route More closely reflects the traversal of a full named route Named based on functional use of road Reference posts are related to this route Departmental Routes: I - Interstate N - Non-Interstate NHS P - Primary S - Secondary U - Urban X - Other State Maintained M - Municipal (city streets) L - Local (other countywide roads) Problem similar to old base route issues

10 MDT Transportation Inventory Environment Departmental Route Example Lyndale Ave 0 Secondary / Urban Interface (Historical) Urban Boundary 5.13 S229 Lincoln Rd U Lyndale Ave 0 Urban Boundary 5.38 S229 Lincoln Rd U

11 MDT Transportation Inventory Environment Departmental Route Example

12 MDT Transportation Inventory Environment Route/Corridor Definitions Signed Route More closely reflects the field naming Jurisdictional boundaries may still influence the route naming Problem route naming subject to political influences and no historical tracking of changes Problem not always unique for road extents (concurrent route names) Problem signed route and reference post is not always unique combination

13 MDT Transportation Inventory Environment Signed Route Example Lyndale Ave Secondary / Urban Interface (Currently) U05809 Urban Boundary S00229 Lincoln Rd 0 US Lyndale Ave U05809 Urban Boundary (New) S00229 Lincoln Rd 0 US

14 MDT Transportation Inventory Environment Signed Route Example

15 MDT Transportation Inventory Environment Example Use and Analysis Roadlog New route log is created on a regular cycle to provide a segmented view of the data for the end users Broken at key attribute changes No GIS interface integrated into the Roadlog, post process to get some spatial reference Provides the linear location in both corridor route and departmental route references per management mandates

16 MDT Transportation Inventory Environment Example Use and Analysis

17 Goals for Updating the MDT LLRS Spatially enable the TIS and LLRS environments with three dimensional coordinate handling Design the LLRS to accommodate a GISenabled maintenance environment Evaluate and simplify the corridor route linear referencing methods Make the system easier to use for field data collectors and powerful enough to meet the LLRS information technology needs Maximize use of existing centerline data

18 MDT LLRS Design Process Utilized GeoDecisions Enterprise Methodology for Application Development Requirements Phase gathered requirements for both the TIS and LLRS environments Design Phase (LLRS) Architecture Design LLRS Conceptual Design LLRS Logical Design LLRS Physical Design Concepts

19 LLRS Design Results Architectural Design Determine the level of integration of business data and LLRS Independent no data sharing between systems (not acceptable for MDT) Interfaced some integration using standardized file formats (not acceptable for MDT) Interoperable shared data and processes with standardized cooperative data flows (acceptable) Integrated fully interdependent systems with centralized administration (too cumbersome and expensive for MDT)

20 LLRS Design Results Architectural Design Proposed LLRS/TIS High-Level Architecture Location/Linear Referencing System LLRS LLRS Maintenance Maintenance Environment Environment (Transactional) (Transactional) LLRS LLRS User User Tables Tables (Transactional) (Transactional) ` ` LLRS Application Interface (With Appropriate Security) ` Centerline Map 1 (Spatially Accurate) Centerline Map 2 (Cartographic) LRM 1 LRM 2 Business Core Segments 1 Length LRM 3 Datum and Route Level LRM n Business Nodes Business Segments 2 Business Segments 3 As Reference (not copied) Published As Appropriate Query Interface 1 MDT Enterprise Repository (Read Only) Linear Centerline (LLRS) Planning ( Road Log ) Query Interface 2 Safety Crash Feeds Appropriate Feeds Appropriate Various Business Systems (Reference Location by LRM) As Reference (not copied) Location Support Features (e.g. PLSS) Maintenance ROW Pavement Bridge GeoTech Transportation Information System (Transactional) Safety Crash Bridge GeoTech ROW Published As Appropriate Traffic MCS Environ ` MDT Boundary Linear Centerline (LLRS) (Read Only) Planning (Links Table) Segmented Structures Pavement Maintenance Environ MCS Other MDT Relevant Published As Appropriate TIS Application Interface Traffic HPMS Fuel Tax Project History ` ` ` Public Land Survey System (PLSS) Cadastre Miscellaneous GIS Features Business Application 1 Business Application 2 Published As Appropriate Business Application 3

21 LLRS Design Results Architectural Design Decision LLRS and business data systems will be separate but interoperable - develop standardized data/process sharing Allows business units to work somewhat autonomously and minimally impacts their business systems especially short-term Location becomes the integration function between the business data features Familiar feel - similar to existing TIS

22 LLRS Design Results Conceptual Design Identify the functional requirements for the LLRS portion of the architecture Determine the structural components of the LLRS data model based on requirements Determine the high-level interaction between the different structural components Components or subsystems Datum Network Route/Corridor Spatial Location LRMs

23 LLRS Design Results Conceptual Design

24 LLRS Design Results Logical Design Defines the entities and attributes that are necessary to establish the subsystems Relationship cardinality between the entities is established PK Entity 3 Entity 3 ID PK Entity 1 Entity 1 ID Attribute 1 Attribute 2 Attribute 3 FK1 Attribute 1 Attribute 2 Attribute 3 Entity 3 ID Entity 2 PK FK2 FK1 FK3 Entity 2 ID Entity 1 ID A Entity 1 ID B Entity 3 ID Attribute 1 Attribute 2

25 LLRS Design Results Logical Design model entities and attributes are normalized Attribute requirements for the standardized linear referencing methods are established dictionary definition for each attribute field is established, including example attributes where not intuitive Considered the end applications in the design Oracle and Oracle Spatial ESRI GIS Products Google Earth

26 LLRS Design Results Datum Subsystem PK Measurement Method Measurement Method ID Measurement Method Type Measurement Equipment Measurement Procedure Establish Date Retire Date PK FK2 FK1 FK3 PK FK1 Anchor Section Anchor Section ID Anchor Point ID To Anchor Point ID From Measurement Method ID Datum Distance Establish Date Retire Date Measurement File Name Anchor Point Anchor Point ID Anchor Point X Coord Anchor Point Y Coord Anchor Point Z Coord Measurement Method ID Establish Date Retire Date Anchor Point Location Desc Anchor Point Level Measurement File Name NCHRP concept of datum (anchor section and anchor point) Separated from network components to minimize breaks in anchor sections Maintains additional stability not accomplished in the concepts of base route in TIS

27 LLRS Design Results 3D Spatial/Cartographic Subsystem Accommodates multiple possible cartographic representations for a single LRS anchor sections Many-to-many cross reference between anchor section and geometry Conflation object?

28 LLRS Design Results Literal Description Linear Referencing Method PK FK2 FK1 PK Reference Feature Reference Features ID Business Source System ID Reference Feature Name Network Link ID Measurement Method ID Reference Feature Type ID Establish Date Retire Date Network Link Offset Business System ID Business Source System Business Source System ID Business Source System Name PK PK Reference Feature Type Reference Feature Type ID Reference Feature Type Name Establish Date Retire Date Intersection Definition Intersection Definitions ID Route ID 1 Route ID 2 Network Node ID Establish Date Retire Date Intersection Name Intersection Description Allows data collectors to reference intersections and key features (bridges) Leverages data in TIS and new route system for automated population Linked directly to network and route subsystems

29 LLRS Design Results Logical Design Linear Referencing Methods Coordinate/Route LRM Facilitates the use of GPS Facilitates map-base data collection processes Reference Marker LRM Uses the green mile post signs (focused literal description) Model allows use of markers with multiple routes/corridor types Control Segment LRM Developed for traffic sections

30 LLRS Design Results Physical Design Concepts Consider the likely applications for further deployment Identify any limitations of application physical data models to accommodate MDT design Consider concessions MDT might have to make to implement logical model in selected products By considering the likely physical technologies in the logical design, the model can be implemented with fewer concessions

31 LLRS Future Direction Spatially Correct TIS Reference Posts and Base Route beginning/ends Eliminate Discrepancies between Linear and Spatial Lengths Modify Business Processes to use Coordinates Spatially Enable TIS Embed/Wrapper Base Route Create Object Fields and Build Triggers in all Tables Correct Links and Modify Applications

32 Questions