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.
Accuracy Carrot
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."
A Break for the Network
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
very fast and looks just like you're at the computer."
In most cases, he said, it runs faster than people's services do on their own desktops.
"Let's say you were looking at some aerial imagery," he said. "You might be pulling 100 MB across the network, whereas the maximum size on the screen shot is typically less than 1 MB."
Jackie Smith, GIS manager of the Houston Planning and Development Department, said agencies running their own individual GIS often caused bottlenecks on the network.
"We do have quite a bit of users doing the Citrix," she said, "because they just can't get the performance otherwise."
Ease and Speed for Users
The enterprise GIS can also cache GIS layers, further improving its speed, said Lee Graham, GIS manager for the Houston Planning and Development Department. Retrieving the various GIS layers in the city's old applications required the applications to "draw" each layer on the map image. This made creating maps a sluggish process, according to Graham. But the system also functions as a mechanism for creating new GIS tools, one of which offers simple icons of precached GIS layers that quickly appear on the maps when clicked."We spent a great deal of time taking our different data sets and building base map layers and aerial photograph layers," Graham said. "The result was Web layers that come up really quickly."
Those layers are available on My City, which is easy to operate, according to Larry McClure, firefighter with the Houston Fire Department. He uses a layer within My City highlighting all fire hydrants in Houston. This helps McClure tell firefighters exactly where to find the hydrants at incident sites, reducing setup time.
"Our hydrants all have unique feature identification numbers. We can just type in a number, click on it, and boom, the map is right there on it, McClure explained. "It has the cross streets and the waterlines. With 58,000-plus hydrants on the ground, it's incredible to have a tool like this."
McClure even said the system was ideal for non-GIS experts.
"For a noncomputer person, anybody can get on that thing," he said, "and you wouldn't even need a class to use it."
GIS Craze Spreads
Accessible and accurate GIS data delivered through My City has spurred a flurry of interest in GIS across the city. Samfield anticipated this and assigned the Department of Planning and Development's GIS Supervisor Larry Nierth to teach classes."They knew there was going to be an explosion of new users who wouldn't have any prior formal training," Nierth said.
Rather than developing his own course materials, Nierth got certified by GIS vendor ESRI to teach classes on the company's ArcGIS Desktop software. The decision saved the city thousands of dollars per class.
"It would cost the city anywhere between $17,000 to $19,000 to have an ESRI instructor come in from San Antonio, which is their regional headquarters, and teach that particular class. It comes out to about $860 per student, per day," Nierth said, adding that his monthly classes don't typically exceed 13 students.
Nierth's status as an ESRI instructor is contingent upon his performance. The vendor monitors his competence via the evaluations his students must submit after each class. Students submit the evaluations online and ESRI receives them immediately.
"They're making sure I'm responding to the students -- that I'm representing ESRI correctly and efficiently, and that I'm knowledgeable," Nierth explained.
Students enter the classes needing only basic computing skills and after a few days, exit with the ability to create GIS maps and edit layers. For example, if a parcel's boundaries have changed, the student can alter the shape of it on the map.
"We have a whole group of folks here who work on streets, addressing and digitizing streets as they're put in," Nierth said. "They're adding new lines and connecting them to the lines already there."
These GIS novices also can edit the data tables behind the layers. The tables list all of the information previously entered for each location.
Reaching Beyond the City
Use of Houston's enterprise GIS is spreading beyond city employees: The Texas Comptroller of Public Accounts is an avid My City user."It gives them a very accurate idea of where businesses are located. If certain businesses are supposed to be paying sales taxes to the city, but they're really close to the city boundaries, then this tells the comptroller's office whether they're in or out of the boundaries," Samfield said, adding that prior to My City, the comptroller lacked a viable source for making that determination.
Fireworks vendors also use My City to plan where to sell fireworks -- which are illegal in the city -- to Houston residents.
"They love the ability to accurately know if a parcel they are considering putting a fireworks stand on is inside the city or not," Samfield explained. "If somebody buys fireworks, in some cases, if they turn left, they enter the city and get a ticket because they have fireworks. If they turn right, they're OK. Now they can even advise people, 'OK, don't go left; there is a policeman waiting behind the billboard. You have got to turn right."
