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Getting on the Map: Underground Utility Location And Municipalities

Getting on the Map: Underground Utility Location And Municipalities. By: Michael L. Gill, PE, RLS. Project:. Capstone project for Masters in GIS – Penn State University Dr Doug Miller – Academic Advisor Dr. Sunil K. Sinha – Technical Advisor

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Getting on the Map: Underground Utility Location And Municipalities

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  1. Getting on the Map:Underground Utility Location And Municipalities By: Michael L. Gill, PE, RLS

  2. Project: • Capstone project for Masters in GIS – Penn State University • Dr Doug Miller – Academic Advisor • Dr. Sunil K. Sinha – Technical Advisor • To investigate various methods to input municipal underground utility locations into a GIS. • Determine the accuracy of the input methods. • Begin to develop a Best Practices for getting legacy data into a GIS.

  3. The Problem: How will we get this mapped accurately?

  4. What we do not see - is the problem!

  5. Every time we dig or need to dig, the problem re-occurs!

  6. Problem Statement: • Municipal utility employees do not know where the facilities are located. • Municipal utility employees need to know where their facilities are located. • How can the legacy data be transformed into a modern GIS?

  7. Extent of the problem: • In 2005, in Illinois alone • 1.22 million “one call” requests • Involved 1,700 separate utilities • 7.94 million potential conflicts

  8. Disruption of utility service Consumer inconvenience Delays in construction Added cost of construction Added utility cost Worker injury Worker death Consequences of problem:

  9. Results of Poor Mapping:

  10. Current utility data location : CADD files Paper Maps Mental knowledge

  11. GIS input methods: Heads-up digitizing Scanning CADD Drawings CADD to GIS file conversion

  12. Traditional location methods: • Soil borings • Test pits • Excavation • Hand • Machine • Potholes • Vacuum • Water jet

  13. New location technologies: • Ground Penetrating Radar (GPR) • Magnetic field-based location systems • Buried markers • Acoustic-based plastic pipe locators • Could these technologies be directly outputted into a GIS? GPR unit & print out

  14. It’s in – but how accurate is it? Can we safely dig where we need to? One-call system accuracy requirements range from 12 to 24 inches

  15. Positional accuracy determination: • Get features into a GIS • Calculate coordinates • Choose a random sample of features • Determine “true” position with a more accurate procedure • Use GPS methodology • Complete a quantitative comparison of coordinates • Do the math (avg, std dev, range, etc) • Understand how the accuracy affects the utility and its location procedures

  16. Research Methods • Capturing Institutional Knowledge • Operators digitize fire hydrant and sanitary sewer manhole locations into a GIS (ArcMap) • Professional Survey Crew GPS’s same point locations (determine “true” location) • Compute locations discrepancies (error distances) for various variables

  17. Research Results -Albion GPS Unit - Trimble 5700 with base station Accuracy 5 -10 mm Base Map: 1m & 6-in Resolution

  18. Research Results - Albion

  19. Research Results - Grayville GPS Unit - Trimble 5700 Rover Accuracy 1-3 m Base Map: 1m & 6-in Resolution

  20. Research Results - Grayville

  21. Research Results - Lawrenceville GPS Unit – Thales Mobile Mapper CE Accuracy Sub-meter Base Map: 1m Resolution

  22. Research Method - Georeferencing • This part not finished!

  23. Breaking the cycle: • GPS both horizontal and vertical positions of underground utilities when: • New construction takes place • During maintenance operations • Fixing breaks • Anytime facility is exposed • Use data to update and improve the accuracy of existing maps.

  24. Goals • Get all underground utilities mapped into a modern GIS system • Have mapped data accuracies to within “one-call” system tolerances • Capture and map vertical data as well as horizontal data

  25. Proposed Location Capture Standards • Existing Systems • GPS all valves, and meters (after digitizing) • Adjust digitized lines to match GPS points • These surface features are directly above underground facilities

  26. Proposed Location Capture Standards • GPS all lines, fittings etc anytime they are exposed of maintenance, locates, repair, construction, erosion or any other reason • Adjust digitized lines to match GPS points

  27. New Systems or Construction • Urban • Capture both horizontal and vertical data to sub-foot location tolerances • Capture location points at all fittings, valves, meters services, etc. • Capture line locations at a maximum line spacing of 100 feet • Keep GIS mapping up to date

  28. New Systems or Construction • Rural • Capture both horizontal and vertical data to sub-foot location tolerances • Capture location points at all fittings, valves, meters services, etc. • Capture line locations at maximum spacing of 500 feet • Keep GIS mapping up to date

  29. Idea to Ponder • Should location capture standards be a requirement the same as pipe material, pressures, etc?

  30. Assumptions & Limitations: • Small sample set • Local in scope • GPS data is more accurate than input methods

  31. Thank you! Questions?

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