Case Study: Konza Prairie Hiking Map

For this case study, we'll consider the following question: What's the best way to map the Konza Prairie? The answer is not simple. When considering a map, many factors must be taken into account in order to get the best map possible. Finding out the intended use and audience for the map is one of the most important of these. From there you can begin the process of determining map format, necessary data, and presentation style.

So, consider the Konza Prairie. In case you're unfamiliar, this is a tract of land just north of Interstate 70 in eastern Kansas. Owned by the non-profit Nature Conservancy, the Prairie stretches over 8,000 acres and is used as a research lab for the nearby Kansas State University. This is a unique area of preserved tallgrass with a great deal of natural beauty. With 7 miles of hiking trails being open to the public, it is also a popular recreation destination.

Let's go ahead and establish some objectives and ideas for this map. It should:

• Show cultural features like boundaries and roads
• Show physical features like forest cover, rivers, and streams
• Show elevation information (this is a rather hilly region)
• Give a good view of the lay of the land
• Be suitable for hiking and show all trails
• Be visually appealing and nice to look at
• Make the visit more enjoyable

The first consideration is the kind of imagery or data to begin with. We can start with the most detailed map available now, a U.S. Geological Survey quadrangle. As you can see below, it is a fairly detailed map that includes most of what we're looking for. There are some notable flaws, however. First, the map was last updated in 1984. Second, there are a number of grid lines, and some are not all that useful for hiking (Public Land Survey System lines, for example). Third, hiking trails are not shown. And fourth, the only elevation description is provided by contour lines. Contours are very descriptive, but often shaded relief enhances a map and leads to a better understanding of landforms. Using the USGS topo as a base, you could create a crude but workable map by simply drawing the trails onto it. But in the interest of correctness, usability, and even beauty, we'll continue to look for other options.

There is another kind of image to consider, one that's widely available. An aerial orthophoto from the USGS, shown below, presents some interesting possibilities. It is clearly inadequate by itself, but the photo provides some vivid images and details that you can't get from the USGS topo. Perhaps it would work to somehow use this as the base and add other information to it. Techniques to add layers of features and improved elevation information can be worked out later.

With a rough plan formed, it's time to get started. The base map is going to be aerial photography, so obtaining the data comes first. The process of compositing, trimming, and placing the imagery (originally in four large files called DOQQS, Digital Orthophoto Quarter Quadrangles) takes some time. In the end, we still have a black-and-white image that looks rather dull. Color would enhance the image a lot, but color orthophotos are not readily available. An alternative is a colorization technique that can be used on monochrome images. It requires precise selection of objects, features, and areas. The process is time-consuming, but worth it. Images below show some steps on the way to a final image, which is at near-natural color.

One very important feature that the photo sacrifices, from an outdoor exploring point of view, is contour lines. How can we get these back? One way is through vector lines. Although accurate and flexible, vectors are not yet available for this area. Producing them from a raster map can be difficult and expensive. Automatic generation from a digital elevation model is also possible, but the results are usually inaccurate and generally unacceptable.

A final option is to just use the lines from the regular raster map shown above. Extracting them will be difficult, but it might be worth it to preserve the original look and content of the lines. The basic process is this:

• Filter out the rest of the image using color
• Erase pixel artifacts that are not contours
• Reconstruct missing parts of contour lines

Part 1 is simple and mostly automatic. However, parts 2 and 3 require a significant amount of work at the pixel level. Good contour lines take time, and this project took plenty of time. The sheer length of all the lines on the map is amazing. Below you'll find a step-by-step look at this process.

Contours and photo imagery go a long way toware creating a usable map. The inclusion of hiking trails was another requirement stated at the beginning. Interpretation of detailed 1-meter aerial photos is the best way to determine the location of trails. Then it's a simple matter of drawing them on as another layer. Showing the boundary of the Konza Prairie would be another useful feature. There are a few other items of interest to add, such as road names and numbers.

Now we have a map that's very useful and colorful. One unfulfilled requirement, however, is that of showing the lay of the land. Contour lines show this well enough, but it often takes some time to interpret them and get an idea of exactly how the hills are shaped. A form of data that can help out in this area is the DEM, or Digital Elevation Model, also from the USGS. A DEM file is a set of elevation samples at 30-meter intervals. When used with the correct software, a DEM file is the ideal way to show terrain

With the existing map we have used as a texture for the DEM, we can create a planimetric map with shaded relief that really brings out the shape of the hills. This stunning image is shown below.

In order to better bring out the landscape, it would be nice to make one last change. Instead of an overhead-like planimetric view, we can switch to a perspective view to better emphasize the prairie landforms. Changing this does sacrifice compass usability, but that should not be a problem since off-trail travel is prohibited in Konza. Scale has also been thrown off, but we can partly compensate by adding UTM grid lines (which form 1km squares). For a discussion of planimetric vs. perspective views, see Perspectives.

Finally, we have arrived! Checking back with the original goals of the map, this final version accomplishes every one. It works well for hiking, much better than the original USGS one. It is also a very beautiful map, showing the area with topographical detail and brilliant colors of the prairie (in summer).

That's all.. thanks for having a look at this page. You should now have a better idea of some of the things that go into making a map. This Konza map is currently in a sort of test phase. To get your own copy, go to the Maps Page.