When we first reviewed the National Map 1.0, we thought of it as a cool (free!) topo map viewer. Today, in version 2.0, it’s much more. It’s now a powerful mapping environment, focused on topography and hydrology, which you can use to view KMZ and KML files downloaded from this site. It also provides the most powerful search tools available for finding geographic names such as streams, canyons, or peaks. You can also use its built in annotation tools to create your own KMLs that you can export to Google Earth or your GPS. Really, if I had to pick only one tool, this would be it.
The National Map is available here: http://viewer.nationalmap.gov/viewer/. When it first comes up, you should see a USA map in the window, with 3 major sets of controls: Data Layers, the Toolbox, and Views. If you don’t see the Data Layers, click on the blue tab near the top left border to expand it; similarly, if you don’t see the toolbox, click on the “Show Toolbox” link you’ll see in the upper right corner of the window.
Loading a KML or KMZ that you’ve downloaded from WildTroutStreams.com is easy: 1) Click on the “Advanced” tab in the Toolbox. 2) Click on the Add Data button. This will bring up the Add Data dialog box. 3) In the box, select KML/RSS as the data type, browse to the file you want to load, and click “Open”. In this example, we’re loading the KMZ of Nebraska Class A Trout Streams.
The National Map will then upload the dataset. Depending on the size of the dataset and speed of connection it may take a while for the dataset to load, so be patient. But after a while you should see the data displayed, in this case, the Class A streams are showing as bright cyan lines. In addition, the “User Added Content” pane will open in the Data Layers sidebar, displaying the header information in the file. From there you can turn display on and off, or remove the dataset from your map altogether.
As with any “standard” web map application, we can zoom and pan to control the view. Here we’ve zoomed in on some of the streams in the Niobrara drainage. It’s a useful “topo” view which emphasizes physical features like rivers, and still shows roads and towns.
But here’s where some of the “magic” of The National Map comes in. Remember the “Base Map View” buttons towards the upper right? Try clicking on the “Hydro-NHD” button. Here’s the same area, at the same at the same map scale as before (note these images are reduced 4x from the original screen to fit on the website, so I apologize if it’s a little hard to read at this scale). Note that the roads and geopolitical labels are gone, and the display is virtually all about water! You see many more streams, and many are labelled. And now (at this magnification) you’re seeing the HUC-10 basins. For a fisherman, what could be better?
This. (Well, maybe not better, but pretty darn useful). Here we’ve zoomed into part of a stream called Long Pine Creek, which is the long cyan stream about 3/4 of the way to the right of the prior image. Here we’ll show two additional views. The first is the “Imagery” view. We now see that the stream enters into a deep, wooded canyon before joining the Niobrara.
Then we switch to “Imagery Topo” view. This overlays physical features on the map and adds contour intervals (these are much more legible when not reduced 4x). We can now readily see that Mullen Rd. provides access to the canyon from the south, and see that the elevation drops about 200 vertical feet from the plateau to the stream bed.
Another powerful feature of the National Map is that most geographic features, even tiny wild trout streams, are indexed and searchable. Here we’ve entered “Hogstock Run, PA” into the search box, and the system has located its mouth (Marker A). You don’t even need the state (though the search will take a lot longer). Once we have a map with a marker, we can zoom in to see the area in great detail.
Generally speaking, the online map views are are useful as paper topo maps. But the old maps showed one feature that’s not available online, and those are trails (which show up as dotted lines). Using the National Map we can also view a scanned topo map to see if it offers any additional info. First click on the “Overlays” tab to return the view to data layers. Then click on the “Other Featured Data” pane and check the box for “Scanned Topo Maps from USA Topo”. Generally, you want to make sure that you’re at a scale close to the original maps (which were generally 1:24,000) before checking the box. Within a few seconds, the topo map image will appear. Note the dotted line. In this case there is an old trail along the stream.
Finally, the printing features of the National Map are extremely useful. It will render the map image on your screen in multiple ways. As a PDF, for printing. Or as a KML which you can then upload as an geo-located image overlay in Google Earth or GIS workstations, and many other formats. Just click on the printer icon in the upper right corner of the screen.
Note, too, you can use the Annotation Tools to draw on the map surface and export them as “vector” KMLs that can be exported to Google Earth or your GPS as tracks or waypoints. The “Setting Up a Trout Workstation” tutorial describes how to do this for a simple example.