GIS

The Urban Forest in Bits and Bytes

20 Mar, 2007 By: Kenneth Wong

Autodesk Plants Inner-City Tree-Tracking Technology in San Francisco


The old oak tree across the street from your house, the knurly juniper outside your window and the tall cypresses along the great highway are all part of the urban forest, the natural foliages to offset the concrete jungle. Perhaps some of them are personal landmarks, the shades under which you used to play as a child. But they don't usually appear on a map. You might be able to zoom into your neighborhood, courtesy of Google Maps, and pinpoint the little fluffy circle in the satellite photo as the red maple in your driveway, but that's about it. If you live in San Francisco, however, you can now do a whole lot more, thanks to the San Francisco Urban Forest Map, built on Autodesk MapGuide.

The San Francisco Tree Map

On March 10, a sunny Saturday, San Francisco mayor Gavin Newsom commemorated Arbor Day by planting a tree at an intersection set aside to mark the occasion. Within minutes, the same tree appeared as a little purple dot in the city's Urban Forest Map, an interactive, online map. For the instantaneous update, the mayor would have to thank Charlie Crocker, a senior product manager at Autodesk Geospatial Solutions. He's the one who logged the mayor's horticultural effort at the site with a GPS unit and a laptop.

The San Francisco Urban Forest Map lets ordinary citizens explore the trees in their city by neighborhood, address and species, among others. Once they've identified a specific tree, or asset, they can use the Ctrl+Click function on the item to obtain more information: maintenance cycle, height, soil type and so on. They also have the option to add a tree that's not yet in the database, a feature that's calculated to encourage community involvement.

Coding the Forest

The Urban Forest Map runs on the MapGuide Open Source platform, created by Autodesk. Alex Fordyce, a senior GIS developer and the founder of Online Mapping Solutions, coded the program in ASP.NET in C# for Microsoft SQL. "The challenge is this," he explained, "We have one tree database from the Bureau of Urban Forestry [BUF], another from Friends of the Urban Forest [FUF]. Each has about 30,000 to 40,000 points [representing trees] in there, and we want to merge both databases into one. The two databases use different schemas, so even though the types of information collected are similar, they have different names in the databases."


The San Francisco Urban Forest Map went online on March 8, 2007. A simple search by address reveals the trees planted within the area as color-coded points.

Fordyce doesn't have the option to alter the two schemas all at once, because "BUF and FUF are working with these databases," he said, "and there are existing processes [field data collection and recording practices] and applications that rely on the current schemas. . . . So developing a common schema is a more complex process than one would think. It's an ongoing process and something that needs to be refined over time." Future integration plans include plugging the collected tree data into STRATUM (Street Tree Resource Analysis Tool for Urban Forest Managers), an urban forest cost-benefit analysis base scale.


A search by species displays the ficuses in the city.

A Balance Sheet for the Urban Ecosystem

"We can actually assign a dollar figure on the benefit each tree provides," said Amber Bieg, development officer at FUF, a community organization. The Urban Forest Map is Bieg's brainchild. "If you plug a tree into STRATUM, based on the amount of carbon dioxide produced, the reduction of storm water, the property value increase, the maintenance costs and the energy saved, you can calculate its cost-benefit ratio to derive a dollar figure."

That's for the commercially inclined folks who want to see everything in black and white on a spreadsheet (or black and red on a balance sheet). But, FUF's Bieg reminds us of the benefits that aren't so easy to quantify: shade and cleaner air, for example.

STRATUM is a component of i-Tree, a peer-reviewed software suite from the U.S. Department of Agriculture Forest Service. According to its makers, communities of all sizes can use it for their forest management efforts. The application is in the public domain and available by request.

For Other Urban Mapmakers

According to Autodesk's Crocker, "The code behind this Urban Forest Map application is going to be made available to the open-source community, so any other cities or urban forest organizations that want to track their trees in a similar fashion can do so without having to develop their own code." Furthermore, GIS developers can modify the existing source code to create new applications: for instance, a program for mapping, monitoring and reporting all the broken traffic lights or street lamps.

Why Is It Important?

On Arbor Day, glancing at the Urban Forest Map projected on an oversize LCD screen inside Autodesk's booth, San Francisco mayor Gavin Newsome quipped, "I'm not sure why it's important, but Wired magazine says it's important, so it must be important."

What Wired says is, "Roughly 80 percent of the U.S. population either lives or works in urban environments, and local governments often struggle with tracking and maintaining their foliage. Typically -- as previously was the case in San Francisco -- troops of volunteers hit the streets with fill-in-the-blank paper forms and old-fashioned maps. Oftentimes, the crew would expect to find a group of trees based on historical records, but instead would find the trees missing (or, perhaps, incorrectly mapped in the first place). Then, there would be the two hours of data entry to set the record straight" (Hack that Urban Forest, March 8, 2007).

Now that the Urban Forest is online on a GIS platform, these manual tasks might be accomplished by a fleet of volunteers equipped with GPS units and handheld computing devices. The mayor's "free WiFi for San Francisco" proposal is still in the works, but if it ever becomes a reality, the BUF and FUF crews should be able to upload their field data to the respective databases right from the work sites.

Personalizing the Trees

The Add a Tree option gives you not only the entry fields for xy coordinates and species, but also a Comment box and a path for uploading a photo. FUF's Bieg hopes that'll encourage people to tell their own personal stories about the inner-city trees that they've come to love and care for.


About the Author: Kenneth Wong


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