Roadside vehicles spray herbicide to control the spread of noxious weeds.		Collected data illustrates the geographic distribution of herbicide, and records various related attributes.		Pump controls on the inside of the vehicle are directly tied to the GPS.

Two roadside herbicide application vehicles maintained by the Weed Control Department are equipped with Midwest Technologies pump controls, hold up to three distinct herbicides, and have four different spray modes (3 foot, 6 foot, 10 foot and 19 foot boom). In 1998, both vehicles were equipped with Juniper Pro2000 dataloggers, which record one position every three seconds when the pumps are activated. Each datalogger is equipped with OmniStar realtime differentially corrected GPS, providing submeter accuracy GPS positions for every location. Each position is attributed by 40 discrete values, recording X and Y position, environmental factors (wind speed, wind direction, etc), mechanical status (what chemicals are being applied through which spray modes), and other variables. These datasets are combined and archived in MS Access, generating over 1GB of positional data annually.

These records are used to keep detailed records of the quantity, timing, and distribution of chemicals applied to any given area. Additionally, they provide a reference geographic whenever ornamental vegetation is negatively impacted by a chemical application. Based on these digital records, the department can make initial assessments on potential responsibility for chemical misapplication, and if necessary, can take further action to assess liability (such as testing soils for chemical residue).

In 2004, one of the vehicles integrated a Midwest Technologies Legacy 6000 datalogger to replace the Juniper Pro2000. The Legacy 6000 collects arcs (lines) instead of points, generating continuous geographic records whenever the pumps are activated. Each of the line features represents discrete chemical applications (multiple line segments are collected simultaneously when multiple chemicals are being applied). These features are uploaded and archived into a geodatabase, where they can easily be accessed and queried if and when the need arises.

In 2008, both MidTech dataloggers will be replaced with Panasonic Toughbook Tablet PCs running ArcPad applications. This conversion will allow increased control in data attribution, and will greatly simplify data management.