GPS Tracking of Clark County Public Works Vehicles

Matt DeitemeyerGIS Analyst

GPS Tracking of Clark County Public Works Vehicles

• A short history of Public Works AVL• Processing data from vehicles with equipment

– ArcGIS (ArcPy)– Python

• Reporting and displaying work activity• Work planning• Customer service

Automated Vehicle Location (AVL)

• GPS modems added to Public Works vehicles in 2012

• Near real time vehicle location– Point location– Bearing– Speed– Equipment on/off

• Managers love this stuff

Good geo-fences make good employees.

The Columbian

Clark County uses GPS to track employeesBy Stephanie RiceColumbian Vancouver city government reporter Monday, June 11, 2012

“On the day last summer that the tracking started in the facilities department, Wilsdon said two employees were to go from where the vehicles are kept behind the Clark County Public Service Center across the street to the Clark County Courthouse. Employees had been notified the tracking system was in effect.

What should have been a two-minute trip took 45 minutes, and managers watched on a monitor as the employees first drove to get coffee and doughnuts.

The employees were disciplined but are still with the county, Wilsdon said.”

“…that system involves more development costs, mostly the time of Bob Poole, the county's Geographic Information Systems manager, and will be an internal system rather than the Internet-based GPS Insight. It will be $500 cheaper per vehicle to operate, however, than GPS Insight, said Pete Capell, director of Public Works.”

Raw AVL Points

Conceptual Mapping Results

Conceptual Consumables

• Customer service• Work planning• Work summary reports

– Operation time– Operation distance (lane miles)– County Worksite (geographic area)– Vehicle ID– Date– Roads sweeping history

Location Analytics: Starting Point

Starting point is a SQL view• Limited to sweeping vehicles• Limited to unprocessed records

AVL data processing• No out of the box ArcGIS solution

Processing Step 1: Point Overly

Processing Step 2: Line Creation• ESRI point to line script• Check each record for:

– Test bearing change from previous point• End line and start a new line when bearing Δ > 50°

– Check for stall; time between points > 2 min– Check for change in worksite – Check for change in linear reference feature– Check for change in equipment on/off

U-turns

Other Line Breaks

equipment on/off

Processing Step 2: Line Creation• ESRI point to line script• Check each record for:

– Test bearing change from previous point• End line and start a new line when bearing Δ > 50°

– Check for stall; time between points > 2 min– Check for change in worksite – Check for change in linear reference feature– Check for change in equipment on/off

• What does this look like in model builder?

Processing Step 3: Line to Events

Processing Step 4: Output

• Event table– Event time – Event distance– Vehicle ID– Worksite– Date stamp

Other Processing Considerations

• Side of Road– Snow Plows

• Measures increasing/decreasing to digitized direction– Increasing = right– Decreasing = left

– Mowers• Average point offset

Other Processing Considerations

• Tracking Same Day Stacked Events– Mowers / Lane Striping

• Multiple passes on the same section of road– Operation miles– County lane miles– Total operational time

Reporting, Planning, and Customer Service

• Back to street sweeping!• Web maps and applications

Conclusions

• AVL processing is possible using ESRI tools, but comes at a cost

• Managers are getting an accurate and uniform measure of work performed

• Opens the door for real analysis• Apple's Phil Schiller: "We don't use any

customer surveys, focus groups, or typical things of that nature"

GPS Tracking of Clark County Public Works Vehicles

Questions?