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Seattle IT remaps during the Seattle Squeeze

When the work and planning to permanently close the Alaskan Way Viaduct started months ago, Seattle IT’s GIS team was preparing to support the process. The team needed to update maps and data for each phase of the Viaduct closure and tunnel opening.

As construction crews made changes in the City’s landscape, Seattle IT’s GIS staff needed to represent each of the changes, in all its products, and do it accurately and timely.

“It was sort of like heart surgery,” said Charles Spear. “You had to take away the organ, which was the Viaduct with all its connections, and replace it with a new organ and hook it up to nerve endings and blood vessels, which were the connecting streets.”

The phases were:

  • To provide an initial update to ensure the network was current as the changes began to occur
  • Support the closing of the first two viaduct ramps on January 4, 2019
  • The closing of the Viaduct and the opening of new sections of Alaskan Way on January 11
  • The closing of the Battery Street tunnel and the opening of the new SR99 tunnel on February 4

At the core of Seattle IT’s response was the City’s Street Network Database, maintained by GIS Analyst Desiree HunterIan Mooser, a GIS analyst who supports SDOT, kept an ear to the ground with SDOT and WSDOT and provided the timing of the phases and the exact opening and closure status.  With each phase, Hunter updated the affected street segments, and those updates fed the rest of the GIS.

A citywide base map image created from GIS data layers served as a backdrop for external-facing applications such as SDOT’s Winter Weather Map as well as internal ones such as SPU’s Utiliview and Field Operations Mapping System. With Products and Services Manager Brian Rosete overseeing the cartography, Developers Arielle Simmons-Steffen and Joel Herd refined a process to pull together all the data and compile the new base map. They passed the resulting routines on to Henry Ho in the GIS Infrastructure group. Ho ran them at each construction phase and posted the resulting base maps to servers for citywide consumption.

Meanwhile, on a similar cadence, Rita Lee and Jacob Jawson, GIS analysts who support Police and Fire, translated the street network changes into a format the dispatching systems could consume. Dispatching the right units to respond to incidents in a two-mile tunnel is a unique requirement. Lee and Jawson had to manually adjust data such as police beat codes to make that happen. This enabled officers to respond in the quickest possible way to emergencies inside the tunnel.

It all went off without a hitch. Users of all these systems saw little or no disruption and worked with up-to-date information at every phase. With a working process in place, the citywide base map is now slated for quarterly updates.