One site, two clicks
- By Patricia Daukantas
- Aug 07, 2003
Hank Garie, executive director for Geospatial One-Stop, wants the e-government portal to be as user-friendly as possible.
Geospatial One-Stop portal uses Web services and open standards to mine existing data
'We're integrating existing things rather than starting over.'
'BLM's Leslie Cone
When you click on the Geospatial One-Stop map viewer and see the word LOADING flash for a few seconds, servers and applications are talking to one another behind the scenes.
The result, custom-drawn on the end user's monitor, is a unique layering of data sets.
The geospatial portal, at www.geodata.gov
, was launched on June 30 as one of the 25 Quicksilver e-government initiatives. Geospatial One-Stop uses Web services that are tailor-made for geographic information systems, hidden inside several off-the-shelf geographic information system applications.
Agency officials and contractors who designed and built Geospatial One-Stop were able to use several other interactive Web applications that agencies have been developing over the last couple of years.
The project was designed to make it easier, faster and cheaper for agencies and citizens to access geospatial data, said Hank Garie of the Geological Survey, who serves as the portal's executive director.
'The portal becomes our organizing gateway, if you will, to allow people to see what's possible,' Garie said.
The portal was designed with the unofficial motto 'two clicks to content,' so that people can find data quickly, he said.
'We've really thought about the usability and worked very hard on it,' said Peter Bottenberg, a senior consultant with project contractor ESRI of Redlands, Calif.
Although Garie manages the portal from the Geological Survey's headquarters in Reston, Va., it's an Office of Management and Budget initiative and a cross-agency partnership, Garie said. Agreements with the Bureau of Land Management and several other federal agencies provide Geospatial One-Stop with funding and staff. Leslie Cone, project manager for BLM's Land and Resources Project Office in Denver, said that her office contracted with ESRI to develop the portal and host the software on the GIS company's servers.Open standards
At the outset of the project, federal officials and representatives of the Open GIS Consortium Inc., agreed to use state-of-the-art open standards as much as possible, Garie said. The consortium, based in Wayland, Mass., established and promotes the Web Map Service (WMS) open standard to make geographic applications work with one another.
'We wanted the portal to be inclusive,' Garie said.
At its most basic level, Geospatial One-Stop is a centralized metadata catalog that stores metadata records in a central Oracle9i relational database in order to speed up searches, Garie said.
The Geospatial One-Stop database contains about 5,000 metadata records right now, he said. Eventually, though, it could contain many more thousands of data sets as more organizations publish their interactive mapping services to the portal.
Publishing simply means supplying the portal's database with the metadata or the URL to a map server. Geospatial One-Stop, with its distributed architecture, doesn't store or host the data sets themselves; rather, buttons link users to their choice of content descriptions, external Web
sites or live map services where available.
The home page groups primary data sets into 17 topic areas, such as agriculture, elevation data and transportation networks.
'This is the cool part of the portal,' Garie said. 'In each of those data categories, we are trying to bring to the fore information and data that we think people need to utilize.'
Visitors also can choose to search the metadata for specific data sets, including those restricted to a particular state or region, or they can zoom in on their locations on the National Map in a separate window.
The National Map itself, at nationalmap.usgs.gov, is a basic map of all 50 states that the Geological Survey built using Web services.
'We're integrating existing things rather than starting over,' BLM's Cone said.
The core technology behind the Geospatial One-Stop includes the Oracle Corp relational database, the ESRI ArcSDE 8.3 spatial database engine, ESRI ArcIMS 4.1 for serving up metadata, and ESRI ArcExplorer Web, a free GIS data viewer, as the map viewer.From here to there
'With one click of your mouse, you're now looking anywhere in the country,' Garie said. 'You've got the water bodies; you've got the roads; you've got elevation data. The Geological Survey has done the integration of those data sets and put them up on the National Map. Inside of the one-stop portal, that becomes our base map.'
Anything in the geospatial portal that's labeled with a 'View Map' button takes users to a map service, Garie said.
Going to the search page and selecting the live data and maps under the Type/Format drop-down menu yields 450 results, representing 450 live map services.
'We did it with one click of a mouse,' Garie said.
For example, the cadastral data section of Geospatial One-Stop presents land-ownership data from two BLM sources, the Land Survey Information System and the GeoCommunicator Land Manager.
Clicking on the 'View Map' button for LSIS launches the map finder tool in a separate window. It takes data from the National Map server in Sioux Falls, S.D., and makes a technical data call to the LSIS server in Denver, which stores the cadastral data on federally owned land.
'The portal has made a call out to both of those servers simultaneously,' Garie said.
The map viewer overlays the data from both data sets on top of the National Map, so that users can see the boundary lines of the federal land holdings that BLM manages, plus any other desired features, such as topography or interstate highways. For clarity, users can control the level of transparency of the overlaid data sets.
'With a couple clicks of your mouse, you have found a wealth of digital data without being a GIS expert,' Garie said.
The map viewer uses data in either of two open GIS standards, OGC WMS or ArcXML, Bottenberg said. The server-side software fuses the disparate data together for viewing through geodata.gov. Bottenberg called it 'truly distributed GIS.'
Saving and linking buttons on the map viewer lets users e-mail a link to the live map service to someone else. The recipient then can call up the same defined geographical area within the same data sets and can pan around and zoom in and out.
Although the interactive mapping services are the cool, cutting-edge feature of Geospatial One-Stop, much of its value will still come from other forms of digital data, Garie cautioned.
The portal takes advantage of the metadata to find data other than interactive maps, Garie said. Depending on the provider, the end user might have to download static data from a Web site or purchase it on a CD-ROM.
The submitted metadata doesn't have to link to Web services, Bottenberg said. It can be metadata about CD-ROM data, Web sites, professional conferences or planned activities.
Even books can be listed, Bottenberg said. For example, a search on the keywords Colorado and gold will uncover a book that has maps of Colorado gold-mining sites.
'We should not minimize how valuable that can be, because in some cases just knowing that data is available, even in offline format, is worthwhile,' Bottenberg said.
The Geospatial One-Stop map viewer includes a button to access databases that lie behind the mapping service. For example, on one New Jersey-based map service called the i-Map Delaware River Basin, a visitor can select a particular boat-landing site, then find its name in the database.
'The portal can open up a wealth of new data sources just by allowing us to look around and search and find new map services,' Garie said.
If more states and counties participate, he said, it could create a deep pool of data available through the portal that could be used for decision-making.Security options
Although Geospatial One-Stop is committed to making digital data accessible through the Internet, its managers can add security, Garie said. Pennsylvania's map service for emergency responders, the Pennsylvania Emergency Response System, requires users to furnish a password supplied by state officials.
ESRI built the map viewer with Java Server Pages, Bottenberg said. It's based on the company's Arc Explorer application for the Web.
Bottenberg said that, offhand, he doesn't know of any other sites where people have tried fusing GIS images to this extent. A production-level system at the scope that Geospatial One-Stop has implemented is relatively new.
The subscription function allows a user to subscribe to a search or a particular piece of geography, Bottenberg said. Visitors can request e-mail notification of new or updated metadata records weekly or daily, depending on the load. They can draw a boundary, add queries to it and save it as a subscribed search.
ESRI pioneered that function in the GeoCommunicator project that Cone headed up, Bottenberg said.
Extensible Markup Language, the lingua franca of Web services, is embedded in a lot of the communications of the system, Bottenberg said.
'What I think is really exciting is that this is the beginning of a national and distributed geographic information system for the country,' Bottenberg said.
Bottenberg praised Garie for his inclusion of the National Map into Geospatial One-Stop. 'The idea of using the National Map as a base map is really forward-thinking,' Bottenberg said.