January 6, 2010 By Andy Opsahl
As many government officials can attest, leading a consolidation effort can earn you enemies rather quickly. But Max Samfield, deputy director of the Houston Planning and Development Department, avoided some of those problems: He opted for a hybrid approach that requires city agencies to add basic data to a new enterprise GIS, but lets them choose whether to publish more specialized data to the system.
As is typical before a consolidation, several city agencies collected and maintained their own GIS data, usually with spotty accuracy. Other agencies bought GIS equipment occasionally, but lacked the staff and expertise to bring it to fruition.
Samfield's solution was to create a repository of newly accurate GIS data delivered to end-users from a central server farm. Agencies then use that scrubbed enterprise GIS data as a foundation on which to build more layers of data using their own specialized information. Agencies can choose to import the scrubbed base data into their own internal map-creation systems, but publishing those additional layers for other agencies and citizens to view is optional.
Samfield had several goals for the new system. First, he wanted the agencies to find the enterprise GIS so efficient that they'd publish their generated layers in the enterprise GIS rather than their internal GIS. Second, he wanted agencies to use the enterprise GIS to create their maps.
Now Samfield's plan appears to be working. Due to wide participation among agencies, dozens of GIS maps are available to city employees and citizens through a delivery mechanism called My City.
When Samfield first surveyed Houston's GIS infrastructure in 2006, he knew the delicate hybrid approach was the most realistic -- simply consolidating everything would have been too complicated.
"There was so much investment in the silos of systems and so much culture organized around those silos," Samfield said. "Some departments employed their own IT staff rather than utilizing the city's central IT. It wouldn't have been easy to dislodge those things."
The meticulous effort Samfield's team put into boosting the accuracy of its GIS data helped agencies take the enterprise GIS more seriously. Five planning and development employees spent two years collecting independently maintained data from various agencies and comparing it for inconsistencies.
"We spent the first two and a half years cleaning up the base map, examining the street center lines, making sure the address range on each block was correct," Samfield explained. "If the address block was missing, we'd enter it. If a street was shown as being the wrong direction, we'd fix that. If the name was misspelled, we'd fix it. If the parcel didn't have an address, we gave it one."
Samfield said consulting firm Idea Integration found Houston's enterprise data had roughly 95 to 98 percent accuracy after the overhaul. This was stunning, given that GIS databases in most agencies are typically accurate around 40 percent of the time, Samfield claimed.
"A lot of cities have systems that look flashy on the exterior," he said, "but that tends to be a thin veneer because once you start working with the actual underlying data, it really relies on the address accuracy."
Another benefit that seduced Houston agencies to voluntarily use the enterprise GIS was that it ran faster than individual agency systems. GIS is especially taxing to networks, which slows down processing for GIS analysts. Houston's centralized system uses Citrix technology to deliver functionality in a way that travels much more easily through the network.
"The way Citrix works is you type at your keyboard and all it sends is your keyboard commands," Samfield explained. "The keyboard commands go and interact with the application server, which runs everything, and what it sends back to your terminal are just screenshots. It's