Once the free downloadable viewing client is available users will be able to explore, fuse, and visualize local GIS datasets and web services. According to ESRI, this next-generation GIS viewing client promises a free, and simple solution for viewing 2D and 3D geospatial data. The kicker… this long-awaited client supports OGC WMS and Google KML data. Buzzwords associated with ArcGIS Explorer – free, fast, fun, open, interoperable, A public beta of ArcGIS Explorer will be available for download in Q2 2006. OF interest is this quote that came out a few months ago... "ArcGIS Explorer is a Google Earth Killer", this from Ed Parsons blog - FYI, Ed is CTO at Ordnance Survey. This will be the obvious comparison and the topic of discussion that will no doubt be quite prevalent once the viewer is released. This also from Ed... "ArcGIS Explorer will be a free 15Mb download from the ESRI website and will connect to a dedicated ArcWeb server farm at ESRI providing an experience similar to Google Earth, although I was not clear where the imagery is sourced from. What got me excited however, is the ability of ArcGIS Explorer to use other data services including OGC WMS and WFS servers and any ArcIMS server you may already use. ArcGIS can also display local data, File GDB’s,shape files, most image formats and even KML files from your PC’s hard drive." 
 
From David Maguire, director of products at ESRI. Maguire maintains a blog (http://gismatters.blogspot.com/) with sporadic product updates and every now-and-then we get a teaser about a application or update. A couple of months back he briefly described some of the specifics of ArcGIS Explorer. Of interest:

• ArcGIS Explorer is a .Net desktop app based on a new lightweight ArcObjects library
• The app is downloaded once from the server and installed locally (just as you would with Google Earth and others)
• The server is the most important part of the system

How it works... Upon start up the client automatically makes a web services connection to a set of ESRI ArcWeb Services globe services. The web services are powered by ArcGIS Server 9.2. A new set of explorer services has been added to the Server core so that anyone (with ArcGIS Server) will be able to create and publish a service. It will also be possible to view ArcIMS and OGC WMS services. As you navigate around the globe, page views are streamed across the web to the desktop application for rendering. All the tasks (mini-applications) are server resident and are called from the client. (Source: D. Maguire)

A screen shot of the ArcGIS Explorer UI (Image Credit: D. Maguire's GIS Matters weblog)

With ArcGIS Explorer, users can expect the following functionality:

• Explore data for the entire world in 2D and 3D seamlessly.
• Fuse local data with data and services from ArcGIS Server, ArcIMS, Open Geospatial Consortium WMS, and ESRI-hosted ArcWeb Services.
• Perform GIS analysis using tasks (e.g., visibility, modeling,
  proximity search).
• Answer geographic questions about the maps you generate and share the results with others.
• Use maps and data from your own secure servers
• View 3D views of buildings and other objects
• View the Earth using a “Globe” scene
• Add data and data services using ArcWeb services or ArcGIS Server (add data from Geography Network)
• Add .kml and .kmz files from Google Earth – note, numerous options for creating your own .kml’s are available, for example, a MapInfo kml writer, Arc2Earth (A2E) soon to be available for ArcGIS users, and many other utilities are now available. See also safe software for their solutions.
• View data using a “swipe” tool.. a very interesting and useful way to compare temporal data (compare before and after scenes) we saw this at the last ESRI user conference when data scenes in Iraq were compared using swipe on a touch table.
• View using a vertical exaggeration in order to improve visualization of elevation data.
• Drape data layers.. for example, drape an elevation map over a 3D topo scene.
• Oen KML/KMZ files directly in ArcMap
   
  Services expected:
• ESRI is likely to provide a set of free base mapping services (imagery, terrain, streets, points of interest) and location services (gazetteer, geocoding, reverse geocoding, computer finder based on IP address, directions, etc.)
• ESRI will also provide some more detailed and specialized services for a fee. 

Basically, the plan is that if we have to pay a lot of money for data/services then we will have to pass this on to users. (D. Maguire)

Finally, of interest to those ArcGIS users interested in making their data available to clients using Google Earth. The Arc2Earth extension  (A2E) from Brian Flood should be a very welcomed addition and handy utility. A2E is the solution that ArcGIS users can use in order to open .kml and .kmz files… you know, the data format supported by the free Google Earth as well as other viewing clients that support KMZ data - like ArcGIS Explorer. This is huge, however, if you don’t plan on opening your wallet you may think again as you should plan on shelling out about $100 for the extension (a bargain price really!) According to A2E developer, Brian Flood, the extension should be coming any time now so stay tuned.  You can catch up on A2E at http://www.spatialdatalogic.com/cs/blogs/brian_flood/default.aspx

Arc2Earth enables ArcGIS users to send their data to Google Earth (Image Credit: Brian Flood)

For more about ArcGIS Explorer:

• http://www.esri.com/software/arcgis/explorer/