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Discussion about Phase 1

Discussion about Phase 1. A polyline feature class will be spatially and topologically adjusted to represent the centerline of undivided roadways and the centerline of both directions of divided roadways, including one-way couplets, ramps, wyes, and frontage roads.

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Discussion about Phase 1

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  1. Discussion about Phase 1

  2. A polyline feature class will be spatially and topologically adjusted to represent the centerline of undivided roadways and the centerline of both directions of divided roadways, including one-way couplets, ramps, wyes, and frontage roads.

  3. The primary reference for spatial adjustment of this feature class will be the LADOTD Pavement Management Systems GPS data. Although the Pavement Management GPS data was collected in the right hand travel lane where possible, the consultant will use their expertise to adjust the public road polyline feature class to the centerline location of all roadway elements.

  4. Intersection of LA 70 & LA 3089

  5. Intersection of LA 42 & LA 431

  6. Ferry Boat crossings will be represented in the final product as a single line crossing the river. The source for these features is BM_FerryBoats. This feature class will be supplied by LADOTD.

  7. Ramps are connecting segments of roadway that are considered a separate travel lane due to a visible obstruction which controls travel. The obstruction may be a raised barrier, grass, or it may be striping indicating an obstruction.

  8. Ramp entering a roadway with a raised barrier

  9. Ramp leaving a roadway with a raised barrier

  10. Ramp leaving a roadway with striping

  11. This is NOT a Ramp. There is no visible obstruction.

  12. LADOTD LRS ID Procedure

  13. REQUIREMENTS FOR A UNIQUE LRS ID IDENTIFIER • The ID must be constructed from existing data elements. • The ID format must be consistent across all segments. • The ID should reflect information about each • segment and its location. • The ID should be different for each side of divided • highways. • The ID should be stable and not subject to change. • The ID should be created considering future functionality.

  14. LRS ID Field in the Public Road Feature Class The field used to create the linear referencing system (LRS) will be named LRS_ID. This field should be a text field of 18 characters. This field will be used for all public roads, both state and non-state maintained.

  15. Determining the LRS ID at Intersections The priority route is determined based on route system in this order - Interstate, U.S., State, Non-State. If the route system is the same, the lowest route number receives priority. Where two non-state maintained roads are involved, priority is given to the road in the south to north direction. The LRS ID for the main and opposite directions of a roadway is based on the information about that roadway. The LRS ID value for frontage roads, ramps, and connecting segments at an intersection is based on the ID information of the priority route. The one-digit Feature Type code (F) is determined based on the relationship of the segment to the priority route.

  16. Determining the LRS ID at Intersections The route number for the state maintained public road feature class segments can be determined by using the BM_STL_StateMaintainedHighways feature class supplied by LADOTD. Once the priority route has been identified and the feature type values have been determined, a three-digit number representing the sequential occurrence of the feature (LLL) can be determined. The sequential occurrence is determined based on the number of occurrences as one progresses along the main direction and the opposite direction of the roadway in the direction of travel.

  17. LRS ID for STATE MAINTAINED ROADS XXX-XX-F-LLL LRS ID for NON-STATE MAINTAINED ROADS PPPXNNNNNNTTTSFLLL

  18. LRS ID for STATE MAINTAINED ROADS XXX-XX-F-LLL The LRS ID for state maintained roads will be created from the existing five-digit Control Section number including a dash between the third and fourth digit (XXX-XX), a dash (-), the one-digit Feature Type code (F), a dash (-), and a three-digit number representing the sequential occurrence of the feature (LLL). State maintained roads will have a twelve (12) character LRS ID which will remain as a fixed identification number for each roadway segment.

  19. Assigning the LRS ID for State Maintained Roads The LADOTD Inventory GPS feature class, DOTD_Inventory_GPS will assist in determining the ends of each control section as well as the feature type to be used in the LRS ID. As with the Pavement Management GPS, this linear feature class represents the “right hand travel lane” of state maintained roads. This data is not meant to be used for spatial adjustment. It is provided to assist the consultant in identifying state maintained roadways and their feature type.

  20. Assigning the LRS ID for State Maintained Roads The Ramps_Uniq field in the LADOTD Inventory GPS feature class, DOTD_Inventory_GPS, contains the feature type code for the state maintained roadways. In addition to the DOTD_Inventory_GPS, the feature classes BM_Couplets and BM_Divided can be used to assist in identification of one-way couplets and divided state maintained roadways. Extensive efforts have been made to identify all state maintained roadways, frontage roads, ramps, wyes, and other connectors, and the feature type of each feature. However, it is the responsibility of the consultant to identify any additional features that may be state maintained.

  21. LRS ID for NON-STATE MAINTAINED ROADS PPPXNNNNNNTTTSFLLL The LRS ID for non-state maintained roads will be created from the three-digit Parish FIPS number (PPP), the one-digit Prefix code number (X), the six-digit Road Name code number (NNNNNN), the three-digit Street Type code number (TTT), the one-digit Suffix code number (S), the one-digit Feature Type code (F), and a three-digit number representing the sequential occurrence of the feature (LLL). Non-state maintained roads will have an eighteen (18) character LRS ID which will remain as a fixed identification number for each roadway segment.

  22. LRS ID for NON-STATE MAINTAINED ROADS • The Parish FIPS number is determined based on the • physical location of the roadway. • The coding for the street naming conventions will • be found in the existing data of the source data. • The coding for the Feature Type will be derived based • on information provided in the LRS ID Procedure. • Discontinuous roadway segments of the same name, • such as Hyacinth Ave in Baton Rouge, and roads that • are UNNAMED within the same Parish will be unique • based on the sequential occurrence number.

  23. Hyacinth Avenue in Baton Rouge with sequential numbers 010, 020, and 030

  24. Unnamed Streets in East Baton Rouge Parish with a blank name value with sequential numbers 010, 020, 030, etc.

  25. Feature Type Codes Main Roadway Codes 1 = Main roadway in the direction of control section or roadway 2 = Main roadway in the opposite direction of control section or roadway 3 = Frontage road on the right side of the direction of control section or roadway 4 = Frontage road on the right side of the opposite direction of control section or roadway Ramp Codes for Travel Lane in the Ramp Codes for Travel Lane in the Opposite Direction of Control Section or Roadway Direction of Control Section or Roadway A = ON ramp from the right of the roadwayL = ON ramp from the right of the roadway B = ON ramp from the left of the roadway M = ON ramp from the left of the roadway C = OFF ramp to the right of the roadway N= OFF ramp to the right of the roadway D = OFF ramp to the left of the roadway O = OFF ramp to the left of the roadway E = Ramp off a ramp to the right P = Ramp off a ramp to the right F = Ramp off a ramp to the left Q = Ramp off a ramp to the left G = Ramp on a ramp from the right R = Ramp on a ramp from the right H = Ramp on a ramp from the left S = Ramp on a ramp from the left Connector Codes V = High Occupancy Vehicle Roadway (HOV) X = Cross-over between carriageways of roadways Z = Contra-flow cross-over between carriageways of roadways U-Turns are designated as a Ramp to the Left for the first half and a Ramp from the Left for the second half.

  26. Sample of LRS_ID for intersection of state maintained roads

  27. Sample of LRS_ID for intersection of state & non-state roads

  28. Sample of LRS_ID for intersection of non-state maintained roads

  29. SAMPLE DATA

  30. A sample dataset of East Carroll and Ascension Parishes is being provided today to show the type of source data LADOTD has available to the chosen consultant. This data provides a base map of Louisiana and will be helpful in determining the state maintained system and the LRS ID for the state maintained roadways. This data will be instrumental as you prepare your proposals. If you need access to DOQQ imagery, please contact Dr. James Mitchell (225) 379-1881 JimMitchell@dotd.la.gov

  31. Sample Data for Statewide Roadway Base Map Project • LADOTD Pavement Management GPS Data • LADOTD Inventory GPS Data Feature • LADOTD Couplet Feature • LADOTD Divided Feature • LADOTD Control Section Descriptions • LADOTD Geographic Features Descriptions • LADOTD LADomain Coordinate System

  32. Sample Data for Statewide Roadway Base Map Project • LADOTD State Maintained Highways Feature • (containing the Surface Type Log data) • LADOTD STL Data Dictionary.doc • LADOTD Parishes Feature • LADOTD City Limits Feature • LADOTD Urbanized Area Feature • LADOTD Urban Area Feature • LADOTD Water Polygon Feature • LADOTD Water LinearFeature • DOQQ Index Feature for 2004 DOQQ Images

  33. Go to: http://www.census.gov/geo/www/tiger/ Select the 2006 Second Edition TIGER Files. In late March, the latest version of the TIGER data should be available at this same site.

  34. Go to: http://tnatlas.geog.utk.edu/downloadfree.htm This website has a free downloadable software, TGR2SHP to convert the TIGER data to shapefiles.

  35. Discussion Concerning the LRS The LRS will be developed from the adjusted polyline feature class using the LRS_ID field as the Route Identifier. Dr. James Mitchell will discuss a few points concerning the creation of the Linear Referencing System (LRS).

  36. Information concerning the LRS creation

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