The latest and most exciting tool in the GIS space is Google Earth (“GE”). Introduced in 2006, as of December 2010 it was entering release 6.0, and its imagery has been constantly updated.  Depending on the state, the imagery is anywhere from a few months to a few years old.  Resolution also varies by state, but for most in our coverage area (the eastern US) it's about a pixel per foot, which is great.

Google Earth is the best tool I've found for “armchair exploration”. (It's also free for non-commercial use, making it just about the best deal on the planet.  You will need a broadband connection). Increasingly, GIS centers are publishing data in KMZ and KML files, which makes Google Earth an important GIS viewer.  There are also free tools that allow amateurs like ourselves to convert GIS data into KMLs.

Currently, GE doesn’t label or index very many physical or stream features (it’s OK with ponds and lakes). However, there is tight integration with Google Maps which, if you put into "Terrain" view, gives you many stream names.  You can also download the NHD kmz file, which will give you even more stream names than Google Maps provides.

Note, the images below were captured using release 1.0 of Google Earth, and the latest interface is somewhat different. Basic functionality and controls are virtually identical, though the newer system works better, has additional features, and better imagery.  We've kept the original illustrations out of nostalgia.  The tutorial gives you step by step instructions on setting this stuff up, using the current release of Google Earth.  Think of this page as just a sampler

In GE, you can start by entering a longitude and latitude in the search line, and the system “flies” right to the spot. A nice feature is that it’s smart enough to figure out and parse different formats. You can enter decimal degree coordinates directly (as we did, just by cutting and pasting them), or Degree/Minute/Second coordinates. Just enter them, GE will figure them out. Immediately you fly into the view shown:

The real power of the system comes from its integration with a 3-D terrain model. You can tilt and rotate the view at will. In the next view, we shifted the viewpoint back a little, tilted the image, and rotated it (note north on the screen compass points to the bottom of the screen). Now we’re looking up the Yokum Brook drainage.

In addition, you can have the system generate driving directions for you, just by right clicking on place points (including the temporary ones generated by the search function). In the next figure, the system has automatically generated driving directions from Stockbridge, MA. It automatically calculates the distance and driving time.

As you can see in the figure, directions are printed on the image next to the turns, and stay there even as you zoom in and out (until you clear them). There’s also one-click integration with Google Maps, so you can print nice road maps of your route, and get the directions in a form that’s easy to read and bring into the car with you. Put Google Maps into Terrain Mode, and you can read off the names of the streams you've found.

Below, we show a more recent release of Google Earth (5) being used as a GIS viewer. This uses the EBTJV kmz files of watersheds, along with some information about Class A wild trout streams from PAFBC.  All of these data are available from the PA Streams page.

A critically useful feature of Google Earth is its integration with Google Maps.  You invoke this by clicking on the Google Maps button in the toolbar (red arrow below).

Google Maps will appear in a window, with virtually the same extent as your original view from Google Earth.  It will appear in what GM calls "satellite" view, which is essentially the same imagery that Google Earth is using.

More useful than satellite view (imo) is the Terrain View.  You get to that off the "More" button at the top of the map window.  By checking the terrain box you get a nicely rendered topographic map.  If you zoom in, you'll be able to see stream names and other features. (see below). Google Maps terrain view doesn't have all of the geographic place names as the "The National Map", and they're not indexed.  Hiking trails and many unpaved roads aren't shown.  But it's extremely easy way to discover a feature name which you can then enter into the The National Map if you need more detail.  Of course, you can always use long/lat coordinates to manually integrate across different mapping systems.