Building an All-Roads LRS Network for Alaska

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Nicholas Willis
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1 Building an All-Roads LRS Network for Alaska presented to 2015 AASHTO GIS-T Symposium presented by Bruce Spear Cambridge Systematics, Inc. Kerry Kirkpatrick Alaska DOT&PF April 19, 2015 Transportation leadership you can trust.

2 Project Background ADOT&PF currently maintains an LRS network of primary roads that is used for managing road inventory data and federal (HPMS) reporting.» 2,864 individual LRS routes» 7,707 centerline miles (calibrated) Primary network (PN) excludes most local roads» ~ 8,600 centerline miles FHWA All-Roads Network of Linear Referenced Data (ARNOLD)» Mandates inclusion of all public roads in a state s LRS network for federal reporting of HPMS and CPRM.

3 Characteristics of Alaska s Road System Road network is highly disconnected» Many communities are accessible only by water or air Southeast (Juneau, Sitka, Ketchikan) Aleutian Chain (Kodiak, Unalaska) Alaskan Native villages throughout the state Many road segments don t qualify as public roads» Pedestrian only (stairways, long private roads)» Restricted Access (military bases)» Trails (logging roads, 4WD trails) Highly variable aerial imagery» Low resolution imagery (30+ meters) in remote areas 3

4 4 Alaska s Primary Road Network

5 5 Project Objectives Create a comprehensive secondary (local) road network using best available data sources» Correct alignments based on available imagery» Identify those roads that do not qualify as public roads Align Secondary Network (SN) to existing PN» Maintain SN as separate roadway feature class» Do not change geometry of any PN routes» Document instances where PN route alignments should be corrected.» Do not split PN where SN segments intersect Create LRS routes for all public roads in the SN» Build routes based on road name and location» Create linear measures along each route

6 Road Centerline Data Sources ADOT&PF Primary Road Network» High positional accuracy (± 3 meters)» Includes all higher Functional Class roads 2008 Functional Class Geodatabase» Developed to support statewide functional reclassification» Centerline geometry acquired from multiple sources» Some ad hoc realignments based on imagery Local roadway databases» 11 Boroughs (out of 16)» 5 Cities and Municipalities» 14 Alaskan Native Villages 6

7 7 Local Road Data Contributors

8 Other Data Sources Orthoimagery» Geographic Information Network of Alaska (GINA)» Additional imagery tiles provided by ADOT&PF Public Web Maps Services» Google Earth and Google Streetmap» Bing Maps» OpenStreetMap Federal Geospatial Data» Census Cartographic Boundary Files» USFS Transportation Layer 8

9 Development Approach 1. Build secondary road centerline network a. Develop criteria for positional accuracy & topology b. Establish template for common attribute fields c. Process each local road database independently d. Stitch processed local networks into a single statewide centerline database 2. Build secondary road LRS a. Select subset of public roads from centerline network b. Create routes based on Master RoadName c. Create LRS measures for each route d. Create point feature database of intersections with PN 9

10 Secondary Road Centerline Network General Criteria» Topologically connected network» Common map projection (NAD 83 Alaska Albers)» Alignment accuracy consistent with GINA imagery Appended Attribute Fields» SrcLayer Local road source database» SourceID Local road segment unique identfier» SrcRdName Local road name from source database» CDS_Num ADOT&PF Route identifier, if available» IsPrimary 1 if road segment is on the PN» NonRoad Type of non-road category» Comment General comment field» LenMeter Calculated length of road segment (meters) 10

11 Secondary Road Centerline Network Processing steps 1. Overlay all centerline networks for an area against GINA imagery ADOT&PF Primary Network Functional Class Network Local Road Network(s) 2. Remove local road segments included in PN 3. Remove duplicate road segments (based on alignment accuracy) 4. Realign remaining secondary road segments to imagery 5. Verify road names and match to ADOT&PF CDS numbers where possible 6. Identify potential non-road segments 11

12 Circle, AK Realignment of existing road segment geometry 12

13 Ambler, AK Realignment based on higher resolution imagery 13

14 Kiana, AK Realignment based on higher resolution imagery 14

15 Non-Road Categories Abandoned Alley Parking Area Pedestrian Way Private Restricted Access Service Road Trail Unknown Other Proposed 15

16 Non-Road Examples Restricted (Elmendorf AFB) Pedestrian - Stairway 16

17 Non-Road Examples Alley (Skagway) Private Townhouse Complex (Anchorage) 17

18 Anchorage Identification of non-public road segments 18

19 Secondary Road Centerline Network Stitch processed local networks into a single statewide network 1. Processed local networks overlaid on statewide PN and GINA imagery 2. Endpoints of segments that connect to PN were snapped to the PN geometry 3. Segments near edges of adjoining areas were edge matched 4. Connectivity check conducted on entire SN network 5. Additional attribute fields appended to SN 6. MasterName field populated ADOT&PF CDS_Number (if available) Place + RoadName 19

20 Create Secondary Network LRS Routes Processing Steps 1. Remove non-road segments from set of potential LRS routes 2. Create unique LRS routes based on MasterRoadName 3. Use ArcGIS Create Route tool to create LRS route measures for each SN route 4. Compare LRS EndMeasure against shape lengths of composite segments to identify discontinuous routes 20

21 Next Steps Locate missing CDS Numbered routes Assign numeric Route IDs to all remaining secondary routes Merge Primary and Secondary Network LRS routes into a combined all-roads network for Alaska (ARNOLD) Establish ongoing database maintenance and update plan with local governments Enhance alignments, topology, and attributes for SN road segments 21

22 Questions? Kerry Kirkpatrick Alaska DOT&PF Bruce Spear Cambridge Systematics 22

LRS Task Force June 13, REVISION HISTORY

LRS Task Force June 13, REVISION HISTORY North Carolina Department of Transportation Geographic Information Systems (GIS) Unit LINEAR REFERENCING SYSTEM (LRS) PROJECT DEFINITION Version 1.0 REVISION HISTORY Date Document Manager Revision Purpose