Using Flex, ESRI delivers next-generation mapping services

by Lauren Gibbons Paul

Founded as Environmental Systems Research Institute in 1969, ESRI of Redlands, California, is arguably the oldest player in the U.S. mapping software business. Long before Google Maps sparked the public's imagination with its rich and easily navigable interface, ESRI sold geographic information system (GIS) and mapping software so state, local, and federal governments as well as other entities could create maps.

As James Killick, ESRI product manager for ArcWeb Services, likes to put it, "We did mapping before it was fun." ArcWeb Services provides a web services platform for developers to integrate mapping, GIS content, and other capabilities into their own applications. Or they can use a hosted version of ESRI software. ESRI has a host of big-name clients, including National Geographic.

What turned GIS/mapping into an overnight Internet sensation? In short, the advent of rich Internet application (RIA) technology, which allows developers to create slick user interfaces unconstrained by HTML's restrictions.

Now ESRI is going beyond these mapping RIAs by offering the ability to create abundantly detailed vector-based maps as opposed to flat, static raster-based maps. Unlike their raster-based counterparts, which Killick calls "static wallpaper," vector-based maps invite users to interact with them in infinite ways, such as viewing a city's topography by its parks or emergency services, rotating a map, or changing its colors.

"Using Flash and Flex, we can provide mapping web services that are next-generation," says Killick. "These technologies open up exciting new vector-based mapping possibilities, including homeland security and safety applications," he adds. For example, if a threat such as gas leak occurred, city officials could use vector-based maps to plot its likely course based on wind conditions and evacuate residents and businesses more quickly and efficiently than with previous systems.

Customers can use the latest ESRI technology to create maps that show everything from homeowner addresses and phone numbers to traffic accident history and flood hazard data. "It's a very rich data set that can be used for much more than simple mapping mashups," says Killick.

In addition to ESRI's traditional user base of government entities, the company is seeing a surge in interest among companies that want to build rich maps for business-to-business and business-to-consumer applications. For example, a retailer might create a store locator for its website. Or a commercial real estate company could sell property location analysis based on ESRI software and services.

"These maps go beyond what you're accustomed to seeing. We provide street maps and access to aerial and satellite imagery as well as shaded relief and topographic maps. We give more context than people are used to," says Killick. 

Vector mapping

ESRI first announced the vector mapping capability for its ArcWeb Explorer and ArcWeb Services customers seven months ago. The application is based on Flash 8 and was built using Flex 1.5

"Flex enables you to write high-level Flash applications very quickly," says Mansour Raad, senior software architect for ESRI. "Flex gives developers an array of reusable widgets such as tables, buttons, text-entry forms, and trees that make programming quicker and easier," he adds.

Flex also eases the task of building interactive connections between the client side of the application and the server. "The process of moving information between the client and server is hidden and efficiently taken care of in the Flex environment. This allows me to focus on what I do well, which is figure out how to display the information," says Raad. "Flex takes care of the infrastructure while you focus on the logic." Raad likes to analogize that Flex provides the application's scaffolding; all that developers have to do is put up the wall panels in order to complete the building.

Adobe Flex 2 also contains additional goodies to make the developer's life easier, including code to access common databases. "It gives you most of what you need to program access to a particular database," says Raad, a Flex 2 beta user.

"The burden on the developer is eased so he or she can concentrate on making the application look and work better for the end user," according to Raad. "Which effects should I use to make it more expressive to the user? You end up concentrating much more on that," he says. "Flex includes special effects, such as fading, that can be used without any fuss," he also notes. 

Stepping up to Flex 2

ESRI is converting its web services applications from Flex 1.5 to Flex 2. "We're proud to be part of the whole evolution. It lets us concentrate on what we do well, which is GIS," says Raad.

Flex 2 features prebuilt connectors and adapters to enterprise applications. "Flex 2 plugs in very nicely to a [services-oriented architecture (SOA)] because of the connectivity to databases and applications. That's very nice," says Raad.

This connectivity enables what Killick calls "collaboration with mapping" in which geographic data can be shared among government agencies in public safety applications, for example. "Because of the vector capability and SOA, I can share objects between maps. I can transmit those objects with vector data to the other party," says Raad. This provides both parties a common operating picture they can interact with and manipulate. So, a police agency in Boston can share data regarding a suspect's last known address with agents in Los Angeles who are tracking him, for example. Thanks to the software's underlying SOA, sharing data across departments, agencies, and governments is straightforward.

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