The Great American Solar Eclipse of 2017 — GIS-style

August 17, 2017

The media is buzzing about the Great American Solar Eclipse that takes place Monday, Aug. 21. 

It’s a historic event that last occurred 99 years ago. To be clear, 99 years ago is when the last total solar eclipse traversed the entire continental United States (lower 48 states).

To put that timeline in perspective, only one of the following inventions existed 99 years ago: FM radio, electric hair dryer, electric washing machine, frozen food, folding wheelchair and “talky” movies. Read further for the answer.

The last total eclipse that traversed part of the United States was 38 years ago, but in 1979 the total eclipse was only visible in five U.S. states (Washington, Oregon, Idaho, Montana, North Dakota). Have a look at the following map of the 1979 total eclipse path through the United States.

Figure 1- 1979 total eclipse path through the US. Source: NASA

Figure 1- 1979 total eclipse path through the US. Source: NASA

It’s painful to think that in February 1979, when this eclipse occurred, I was a junior in high school in Oregon, living right in the path of the umbra (the moon’s shadow). I don’t recall the 1979 solar eclipse, but that doesn’t surprise me given the mind of a 16-year-old, at least mine.

Or, it could be the fact that was about 8:15 a.m. in February. Februaries in Oregon can be depressing due to the lack of sunlight. Anyway, it’s painful because today there are 37-year-old adults who were born after I graduated from high school. Time has flown by.

One of the points I was going to make in this article is how much GIS technology has improved since the last total solar eclipse in 1979, but that was 38 years ago. Given Moore’s Law, it should have improved exponentially in the past 38 years, and it has.

One way the evolution of GIS is displayed are the maps of the Great American Solar Eclipse of 2017. Let’s start with this basic one illustrating the path of the moon’s shadow as it traverses the United States:

Figure 2 - Solar Eclipse 2017 path. Source:

Figure 2 – Solar Eclipse 2017 path. Source:

My office is in Lake Oswego, and my house is just east of Lake Oswego, as illustrated here:

Figure 3- Solar Eclipse 2017 Oregon path. Source:

Figure 3- Solar Eclipse 2017 Oregon path. Source:

As you can see in the above map, my house and office are really close to the 100 percent eclipse path. In fact, using the following interactive map, I determined that from my house the sun will be 99.77 percent eclipsed.

Figure 4- Interactive 2017 Eclipse Map (click to explore the map). Source: NASA

Figure 4- Interactive 2017 Eclipse Map. Source: NASA

Now, for some cool animations. Back in 1979 (even 2000), animations were tough to produce. With today’s computing power and software, it’s quite straight-forward and quick to produce high-quality animations. The following is a screenshot from a 48-second animation from NASA’s YouTube channel showing the path of the total eclipse.

Figure 5- 2017 Solar Eclipse animation (click to play). Source: NASA

Figure 5- 2017 Solar Eclipse animation. Source: NASA

As GISers, you know that software is the engine. Engines need fuel to run. With GIS, fuel is data. For this next animation, two key pieces of data enable a new level of accuracy in plotting the umbra.

The first is the topography (surface map) of the moon. It’s not as round as it appears from Earth. Its surface has jagged edges from varied terrain just like the Earth.

The second is the vantage point on the Earth. In producing the following animation, NASA used SRTM elevation data collected from the Space Shuttle Endeavor mission in 2000. In 2014, the U.S. government released high-resolution SRTM data (30-meter) to the public. As a result, the following animation incorporates high-resolution data with unprecedented accuracy.

Figure 6 - 2017 Solar Eclipse animation using high-accuracy topo and SRTM data (click to play). Source: NASA

Figure 6 – 2017 Solar Eclipse animation using high-accuracy topo and SRTM data. Source: NASA

Where are you going to be on August 21st?

The fascinating part of this event is that no matter where you are located in the continental United States, you’re going to experience the effect of the solar eclipse.

As I mentioned above, at my house and office, I’ll experience about 99.77 percent eclipse. If I drive 15 miles south, I can experience 100 percent eclipse. The challenge is going to be traffic. It is expected that a few hundred thousand tourists will visit Oregon for this experience.

Traffic is already heating up. Gas stations may run out of fuel. Grocery stores may run low on food. I have no idea what to expect for traffic if I decide to make the 15-mile drive. I assume country roads as well as I-5, Oregon’s major interstate road, will be jammed and everyone will be driving at a snail’s pace and when the actual event is in progress, stop on the side of the road.

If I was a betting man, I’d say I’ll make the trek with a tank full of fuel and a sack lunch (~10:15am is go-time in Western Oregon). I’ll take one piece of equipment to document the event, my drone. If I plan it right, I should be able to grab some incredible images, not necessarily of the solar eclipse itself, but of the crowds of people mesmerized by the event. Follow my Twitter for updates.

Lastly, it was the electric washing machine. That’s the only invention listed in the opening paragraph that existed in 1918, when the last event like this occurred. The next one won’t be until 2045. I think I’ll make the 15-mile drive on Monday.

2 Comments on "The Great American Solar Eclipse of 2017 — GIS-style"

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  1. Art Kalinski says:

    Do it. We’re driving 60 mile north to experience totality in Tennessee. I experienced a 90% eclipse years ago and it was no big deal but two friends told me that 100% was a completely different and surreal experience not to be missed. We’re also tailgating rather than relying on restaurants.

  2. Eric Gakstatter Eric Gakstatter says:

    I’m going to try to do it Art. Traffic is going to be ugly so we’re planning our routing this weekend. There is not a hotel room available in sight, and I bet AirBnB is making a fortune this weekend.

    Tourists could add 25% to Oregon’s population this weekend.