Making and Printing Custom Maps
Maps are phenomenal resources, but sometimes what you need just isn’t available. Perhaps the detail isn’t sufficient, or maybe the area you plan to explore isn’t on the maps you can find. Making and printing your own custom maps can be a worthwhile way to spend some time on a rainy day while you wait for an opportunity to get out and explore!
There are several sites on the internet where you can create custom maps, but there is one that I prefer above all others I have used - CalTopo. CalTopo is a website that allows you to create highly customized maps, from basic topographic maps to more complex maps that may include contour lines, cell phone coverage areas, and labels for roads and other features on top of an aerial image.
Let’s take a look at how to make a map in CalTopo. As a quick note to ensure there is no confusion, I’ll be working on a computer rather a smart phone. There are useful features on the mobile version, but the desktop version has more functionality for making printed maps. CalTopo has many features that I will not go over in this post, so click around to find out what all the buttons do. I will just focus on making the type of map that I might typically use while out and about.
To start creating a map, go to caltopo.com and click “Start Mapping” in the upper right-hand corner of the screen. Once the map loads and opens, you can search for any location you wish to make a map of. I worked in Bannack State Park in southwest Montana for a year and I’m quite familiar with that location, so I’ll make a map of Bannack. There is a list of map layers on the right side of the screen. This is where you will set the Base Layer and add any additional information you would like to the map. I will use the “Global Imagery” Base Layer and add “Contours” and “Public Lands” on top of it. Within the map viewer portion of the screen, you will see a legend that tells you which color represents which type of public land.
Now that I have applied the map layers I want to use, I need to determine how much ground I want the map to cover. Below the zoom buttons on the left-hand side of the map viewer, you will see a printer icon. Click this to open a new menu on the left side of the screen. The rectangle that now shows up in the map viewer is the area that the map will cover when it is printed. The dot in the center of the rectangle is where the map will be centered. Click and drag to move the rectangle and center the map where you wish. You can change the orientation between portrait and landscape view depending on whether you prefer more map coverage to the north and south or to the east and west. I set mine in landscape view for this example.
Now that everything is set for the layers, location, and orientation, it’s time to set the scale so that it prints in a usable format. In the left-hand menu, you will see a drop-down box labeled “Scale” under “General Settings”. The default setting is “Not Fixed”. Clicking on it, you will see a selection of options to set the scale at a particular ratio of 1:XXXXX. However, these settings will not accurately match the same scale on a grid reader or the scale on a compass when printed. I choose to use “Custom” instead and set the scale so that it will match a map reader scale as closely as possible. I like to use the 1:24,000 scale reader on my Suunto MC-2G compass, so I will input different numbers until it is close enough that I’m comfortable with it. I have found that 1:23,100 matches the scale reader on my compass pretty well. It’s not perfect, but it’s close enough to navigate with confidence, especially if I take terrain association and other navigation methods into account. Play around with the number until you are satisfied with it. It may not seem like making a map this way would be accurate, but it’s accurate enough for the navigating I do when I’m out and about. I have compared my location on a GPS to my location on a map set at 1:23,100 using a 1:24,000 grid reader with UTM coordinates, and the difference is very, very rarely significant.
At the bottom of the “General Settings” section, there is a field where you can type in a custom map title. This will print on the map once you are done.
Another option I will often use is “Grid Lines”. There are check boxes for “UTM” (Universal Transverse Mercator) and “Lat/Lng” (Latitude/Longitude). I rarely use the “Lat/Lng” grid, but I find the “UTM” grid very useful. Next to each check box is a drop-down box where you can set how the grid lines appear on the map. For the “UTM” option, that is how big each square will be. I often leave it as “Auto”, but it can be changed if desired. Below the check boxes is another drop-down box labeled “Datum”. If you will be using the grid lines, make sure you choose the correct option to match your GPS unit. The two options available on the map are “WGS84” and “NAD27”.
Once everything is set, click “Generate PDF” and the map will open in a new tab. Once the map is open in the new tab, it is ready to print. If you would like to print it as a JPEG or order a paper map, there are additional options at the top of the menu under “Format”. I have only ever used the “Geospatial PDF” option.
Now that you have your very own custom map, it’s time to get out and explore!