Here's How to Make a Map for Those of Us Who Can't Draw a Line
I suck at drawing, and odds are you do, too. One of the great things about computers is that they do the work for us. We have spell check to save us from those embarrassing tyops and calculators for hassle-free math. For those of us who love maps but can't draw, there are programs that create great maps with little skill needed.
For the past couple of months, I've created maps for The Vane for events ranging from hurricanes to flash floods to all of the tornadoes we've seen since 1950. They're not the prettiest, but they're functional and convey the information necessary.
Every time I make a map for a post, I get emails and messages asking me how I created them. The ability to create one's own maps is a coveted skill among weather enthusiasts, and some folks like my good friend Jordan Tessler (the brains behind TerpWeather) hold geography degrees and make some of the best maps on the web.
If you're like me and have absolutely zero education in GIS (Geographic Information Systems) software, which is what people use to make those cool-looking maps, fear not! It's actually really easy once you get the hang of it.
As with every field, GIS programs range in quality and price from "free" to "take out a loan." If you've got the disposable income and you're willing to go all-in, ArcGIS is the top map making software available on the internet. If you're broke or cheap (or both!) and would rather stick to the freeware, the two best programs you can use are MapWindow and QGIS.
MapWindow is a bare-bones but powerful piece of software that creates great maps with a slight learning curve. MapWindow is the program I've used to make all of the maps that have The Vane's logo on them. QGIS, on the other hand, has more features and by all accounts is the most powerful freeware available (strongly mimicking ArcGIS), but it has a steep learning curve.
For the purposes of this post, I'll talk about and use MapWindow as an example.
Shapefiles (.shp) are the bread and butter of GIS software. These are the files you'll use most often when making basic maps. County shapefiles hold the information GIS software uses to draw county outlines. The shapefile titled "al092008.047_5day_pgn.shp" from the National Hurricane Center draws the cone of uncertainty for Hurricane Ike from the 400PM forecast on September 12, 2008.
Here's a list of websites that provide commonly-used shapefiles for severe weather:
- Severe weather outlooks from the Storm Prediction Center
- Hurricane forecasts (past and present) from the National Hurricane Center
- Historic tornado, hail, and wind reports from the Storm Prediction Center
- Watch, warning, and severe weather report shapefiles from the Iowa Environmental Mesonet
- Various shapefiles from the National Weather Service
- Shapefiles from the Census Bureau
Opening up MapWindow GIS at first can be intimidating because it's a blank screen with a bunch of buttons. The first thing you need to do is click the green "ADD" button up at the top; this button lets you add shapefiles to your project. If this is your first time using MapWindow, it should open to a "sample projects" folder that has a great library of default shapefiles for world countries, states, bodies of water, and U.S. counties.
Here's what it looks like when you open up the "states" shapefile for the first time:
To edit the feature, you need to have the legend panel open (on the drop-down menu, click View > Legend). Double-clicking the shapefile on the legend window brings up a prompt that allows you to change the colors of different features. Once you have your base map to your liking (states, counties, cities, lakes), be sure to save it as a project so you can quickly edit it without having to start from scratch every time.
The "categories" window is probably the most important as it allows you to isolate and change the appearance of different features. In the above image, I isolated "TCWW" in one of the NHC shapefiles to show the different warnings in effect ahead of Hurricane Ike back in 2008. "HWR" is "hurricane warnings" and "TWR" is "tropical storm warnings."
After thickening the lines and changing the former to red and the latter to blue — as well as editing the cone of uncertainty, forecast points (showing the different hurricane/tropical storm symbols along its forecast path), and adding labels — I came up with the final product.
The "categories" feature is pretty useful. In this map, I used it to color-code the counties in Alabama based on population per square mile:
Just a few months ago when I first started creating maps, they were terrible. Terrible. Here's a look at one of those affronts to information visualization, complete with the awful legend down on the bottom-left corner:
Instead of having to draw a legend onto your map in your image editor, a good shortcut is to create legend templates using Microsoft PowerPoint. You can copy/paste the legend directly from PowerPoint to your image editing software
Creating a template like this makes it easy for you to create a legend in less than a minute and provides map-to-map continuity.
Going from a saved, pre-made project to a finished product (downloading and adding shapefiles, filling in the legend, and throwing them together in the image editor) usually takes about 4 minutes for hurricane maps, and a little longer for other types of severe weather.
On its website, MapWindow provides several tutorials (in PDF format) on how to use its software to create maps. It's pretty intuitive once you start clicking around and figure out which features alter different parts of the map.
If you're a weather enthusiast who's always wanted to make your own maps, this is the way to do it. It gives you the satisfaction of having done something yourself (rather than copying/pasting from the SPC or NHC) and it gives your page a unique look.
[All images by the author]