Bentley Forges GIS Tools to Build 3D Cities

26 May, 2010 By: Cyrena Respini-Irwin

The latest infrastructure-management software enables city officials to model their domains more realistically and completely.

If you live in the United States, odds are good that you live in a city — a complex network of infrastructure that encompasses buildings and bridges, subways and sewers, freeways and fire hydrants. More and more city governments are turning to geographic information systems (GIS) to better manage the masses of data involved in such a multifaceted system.

Furthermore, those already making use of GIS are increasingly transitioning from 2D to 3D systems, which enable more sophisticated simulations, analyses, and disaster mitigation efforts. The value of 3D is also apparent to nontechnical stakeholders, who can more easily comprehend the impact of a proposed highway overpass or waterfront development project when it's presented in a realistic, familiar format.

"[You need] that 3D component to visualize, analyze, and manage city infrastructure," said Damon Dougherty, product marketing manager for Bentley Systems' geospatial product line. Bentley demonstrated that belief earlier this year, when it released V8i (SELECTseries 1) versions of its portfolio of 3D GIS software. Users can access information from spatial databases, drawings, and other sources with Bentley Geospatial Server; create and edit 3D objects and renderings with Bentley Map; process and edit images in Bentley Descartes; and publish their 3D city models with Bentley Geo Web Publisher.

Francois Valois, senior product manager for geospatial desktop products, explained that Bentley Map — a desktop analysis and editing application built on top of MicroStation — offers 3D editing capability and features that go beyond CAD. Users can build a 3D model with photogrammetry or LIDAR data, then, with the help of Decartes, texture it with pictures taken on the street. "You can create a high-quality 3D scene at low cost ... any camera will do," said Valois.

Bentley Map's integration with Safe Software’s FME Desktop technology enables the use of 3D formats such as CityGML, "a format that's been standardized worldwide," said Dougherty. The new Map release also offers an application programming interface (API); "The development platform allows you to extend what we offer," said Valois. "We're developing open products," Dougherty concurred, "so [Map] can be customized."

The Benefits of Three Dimensions

According to Benoit Fredericque, product manager and director of the 3D GIS project, "The real benefit of 3D modeling is to support communication between people, and Google Earth is a really good medium for that." The Google Earth capability is provided by Geo Web Publisher, which can also create interactive web pages and 3D PDF files. Dougherty explained that with these methods, interested parties don't need to have Bentley software to see what the impact of a street closure or other project might look like.

Bentley Map can publish 2D or 3D maps to intelligent PDF files and PDF map books.

There is more value to 3D GIS, however, than communicating city planning developments to concerned citizens. Valois explained that line-of-sight, flight-path, wind, noise, and solar exposure analyses "can be solved uniquely with 3D data." In addition, 3D buffering helps decision makers determine how many people would be affected by an explosion, flood, gas cloud, or other wide-ranging disaster.

3D GIS is also especially well suited to infrastructure management purposes. "The 3D model provides a unique interface to store and discover data ... [it's a] really efficient way to manage engineering content, which by its nature is 3D," said Fredericque,

"Engineering has been doing 3D for many years. It's unfortunate that a lot of the source data fed into GIS has been generalized to the point that we're losing 3D data," said Dougherty. "Five years ago, we didn't have the hardware or the data storage [necessary to preserve all that data] ... now, everything's coming together at the right time."

3D Across the Globe

Dougherty explained that as initial model creation has become faster and less expensive, there are fewer hurdles to adoption of 3D city GIS technology. Valois noted that LIDAR, both terrestrial and airborne, has become far more accessible. "With a small budget you can still do a lot," said Valois, noting that cities may start with a 2D footprint and work up from there. Users can also limit costs by detailing only certain portions of the city, such as the downtown and business districts, instead of every neighborhood.

In addition, the technology is becoming more widely used, both inside and outside the United States. "It's becoming mature, it's becoming well accepted," said Dougherty. Strict regulations requiring cities to perform certain analyses, such as noise analysis, are driving adoption in regions such as Europe. "I think we're really at the end of the early adopter phase globally," Dougherty continued, predicting "a very strong incline in adoption."

Fredericque observed that many local governments don't realize they possess a great quantity of existing data, likely scattered among various city departments. "They already have enough information to get started today — they just need to think about their workflow."

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