By Jessica Kane

Recently, Brian "Koz" Kozminski, a local fly fishing guide who owns True North Trout, contacted us about developing a custom map graphic for presentations. Koz is doing a number of presentations for Trout Unlimited about Northern Michigan rivers and had been on the hunt for a good map for a while. Most of the maps out there are either A) extremely detailed maps meant for navigation to and from certain points on the river or B) higher-level views including many other types of data such as roads, county lines, etc. What Koz wanted was a regional map focused on highlighting specific rivers of interest in a way that would help his audience visualize their locations.

Step 1: Import Data Layers

The first thing I needed was the lakes and rivers data. These data files are publicly available and easily edited with a Geographic Information System (GIS) application like QGIS. I imported a number of files including lakes, rivers, cities, roads, townships, etc. Each of these data types are in different layers that can be turned on and off using the Layers tools visible in the lower left of the screen. In the image below you can see that I have all the layers clicked off except for the lakes and rivers data. The Great Lakes layers provide the iconic outline of Michigan’s Lower Peninsula and the lakes and rivers serve as the starting place for editing.

Step 2: Select Attributes

Although the image above is pretty cool, there is just too much data. It’s overly busy and has no clear focus. So the next thing I did was select only the lakes and rivers I wanted in my final map. This can be accomplished through running layer level queries and/or doing hand selections of map features. We’ve used a mix of the techniques to provide the desired results. Once selected, I saved these to new, working layers.

Step 3: Import into Vector Graphic Editor

Once I had the specific data that I wanted, I set the layers up for export and exported the file to a PDF. Now I had a file that could be imported into a vector graphics editor like Inkscape. Vector graphics editors are used to edit digital images/graphics that are made up of lines and shapes (instead of pixels, like a jpeg/bmp). Once I had the file in Inkscape I could edit all of these lines and shapes to smooth things out, change colors, add logos, etc. Inkscape also works with layers so I could put the base map on one layer, put the rivers on another layer and put the logo on a third layer. Locking and unlocking these layers allowed me to edit specific parts of the image without affecting other parts.

Step 4: Edit and Stylize

The first thing I did was simplify the nodes in the image. Nodes (aka vertices) appear along the lines in the image at every point where the line changes direction.

The image on the top was taken before I simplified the nodes. The image on the bottom was taken afterwards. As you can see, simplifying the nodes removed many, many data points and smoothed out the lines. Deleting all unnecessary nodes cleared up the image and made it smaller for easier editing and exporting.

The rivers also needed attention since in many places they were composed of lines upon lines, making the rivers appear to have rough edges. By zooming in on the desired locations and deleting some nodes while moving others around, I was able to smooth out the river lines, giving it a more fluid look.

Koz wanted to help us get our name out with the designs, so I imported our logo into a new layer and moved it to the desired location. I changed the color scheme by using the Find and Replace tool. Instead of using a color tool or manually trying to change all of the lakes and rivers from one color to another, I was able to tell Inkscape to find all of the old color and replace it with the color I wanted. Lastly, I added text boxes for the river names and town names, adjusting the color to place emphasis on the rivers.

Step 5: Export to Image File

Once everything was looking like I wanted, I exported to an image file for use by Koz. Looking at the final map below, you can see that I chose to leave a moderate amount of detail in the lakes and coastline but really simplify the river tributaries to simplify interpretation of the rivers. How much detail to include always depends on the audience and the intended use of the map. It’s fun to think about all those data points in tables ending up as this beautiful visualization.

If you want custom maps and don’t want to go-it-alone, call us at (833) 254-6345 or send us an email at contact@line-45.com to schedule a free consultation.

Happy Mapping! Jess