Mosquito Abatement Expressed in Real Time

Fort Collins, Colorado, Publishes Live Web Map on its West Nile Virus Prevention Efforts

The city of Fort Collins, Colorado, monitors the threat of West Nile virus, a typically mosquito-borne illness. Recommendations from the Health Department prompted the City Manager to recommend that action be taken in the form of a mosquito-spraying operation that could be monitored in real time on the web.

By Matthew DeMeritt, Esri

Another mosquito season was underway in Fort Collins, and the threat of West Nile virus had reached a dangerous threshold. In developing the communication plan for the mosquito-spraying operation, the Communications and Public Involvement Office determined that there would be a public benefit in providing near-real-time locations of spraying vehicles via web map. The IT department decided to create that mechanism with ArcGIS.

The Mist

Marcus Bodig, GIS Manager at Fort Collins IT, focused on fulfilling the assignment to create a website that delivered near-real-time reports of truck locations so that citizens could anticipate when the spray vehicles would be in their neighborhoods. Spraying was scheduled for evenings and nights, a popular time when residents would enjoy their backyards and patios. Near real-time tracking of the trucks would allow community members to bring pets indoors, cover gardens, and close windows before the sprayer arrived.

On paper, it looked easy. All trucks had CompassCom GPS installed, so representing each spraying vehicle’s location on a map for citizens to view had popular precedent. Bodig would simply have to transform tabular location data for graphical display in a fleet-tracking web map.

Desktop view of zoomed-out map showing spraying vehicle location. Red trail indicates age of 30 minutes.

“CompassCom works with our Streets department, so they already provide GPS information for their fleets by writing location data in Oracle tables,” Bodig explains. “We converted those coordinates to XY events and then shared them through ArcGIS for Server, expressing it all in an HTML5 website.”

The resulting web map showed the location of its spraying fleet with a dotted line behind the trucks marking the route they travelled. The dots were color-coded for age.

“I built a 5-minute auto-refresh to generate updates, so it was as near real time as we could make it,” says Bodig. “It looked like a simple solution that would work — except there was no time to test it properly.”

(SPOILER ALERT: it didn’t work.)

Leading and Bleeding

The site’s performance failure had much to do with the short time frame and the pitfalls of premature promotion.

“What we didn’t know is that when the site was launched, it was accompanied by a full-on media blitz,” said Bodig. “The Communications department was doing press for it while we were putting the final touches on the website.”

To those already concerned about the site’s capacity, that was worrisome. Viewership became much bigger than anticipated when the Denver evening news mentioned that the department would have live tracking on the site. Things went south when thousands of requests began jamming the site later that evening. As the number of requests overloaded the server, requests timed out due to sheer volume. Many smiles turned upside down.

Another layer records a vehicle’s 6-hour location history.

“Every time the users refreshed the site, it was actually performing an add XY event for every person refreshing,” said Bodig. “We found out later that the table we were querying was actually on a test database, so it wasn’t even on our production Oracle environment.”

After a preliminary post mortem, Bodig created an alternative solution — capturing and posting PDF maps of spraying in progress, refreshed every 15 minutes. That didn’t quite match the “near real-time” capability the department initially wanted, but it was the best that Bodig could put together between spraying dates.

Determined to get it right, the department began looking into a more distributed solution impervious to visitor logjams.

Digesting the Stream

While attending the 2013 Esri User Conference, Bodig had his eyes peeled for something that would offload the city’s “XY request” burden. There, Esri introduced the world to the GeoEvent extension for ArcGIS for Server. An Esri representative told him that he could use GeoEvent to write features to ArcGIS Online rather than on the city’s physical server. That was exactly what they needed — a fault-tolerant cloud-based system invulnerable to bottlenecks.

“GeoEvent is designed to process all this information and make it digestible,” says Bodig. “It processes the live data stream coming from CompassCom and populates the map with a real-time picture of truck locations.”

The city only pushes the live map when spraying actually takes place. In 2014, the county decided to spray and the city configured their site for them to use. Everything worked perfectly this time around. Fort Collins is now ready to serve live maps without worrying about slowness.

Adaptable to All Fleet Tracking

Since fixing its mosquito abatement mapping, the city has adapted the same ArcGIS Online/GeoEvent combo to track the progress of snowplows. The map is viewable and live continuously through the winter whenever the snow falls so citizens can be informed of cleared roads.

To see Ft. Collins web maps, visit

For more information on GIS applications for public works, please visit