A History of California Wildfires

Category: Best news application

Country/area: United States

Organisation: Capital Public Radio

Organisation size: Small

Publication date: 24/01/2019

Credit: Emily Zentner, Chris Hagan, Sally Schilling

Project description:

This is an interactive map showing the perimeters of more than 100 years of California wildfires using geodata from the California Department of Forestry and Fire Prevention (Cal Fire) and the U.S. Geological Survey. Because of how data were collected prior to 1950 and Cal Fire’s criteria for recording a fire’s perimeter, we can’t say that this represents every single fire that has burned from 1878 to 2018, but we can say that this data is the most complete record of California’s fire perimeters, according to Cal Fire.

Impact reached:

In addition to this map being one of our website’s most viewed pages in 2019, there was an amazing community response around the state to it. This map was shared in a number of community public safety pages, fire victim support groups and firefighter groups on Facebook, where we saw interesting conversations about the state’s history with fire. We even had a Cal Fire chief reach out to us to ask if we would be making prints of the map as he wanted one to hang in his office.

Researchers from around the country have reached out to us asking for the data that powers the map, including from the University of Chicago and our local University of California, Davis. These researchers plan to use it in studies about everything from fire science to the wildland-urban interface. We are hoping to make this data available for download on our site in the future. The map is also currently being used in the curriculum of the Los Angeles Unified School District.

Wildfire is arguably the biggest issue facing California now, and this project provided important context to the megafires that have burned in the state over the past few years. We saw comments from community members that the map was a “sobering” representation of how extensively fire has touched the state. We also heard from people who “nerded out” over what areas the fire has burned over and over, like the area around where the Camp Fire burned in 2018, and what areas haven’t been touched, like the Central Valley. Overall, from the reactions we got, we can say that this map helped people better understand California’s relationship with wildfire going back over a century rather than just in recent years.

Techniques/technologies used:

When Emily first downloaded this data from Cal Fire’s website, she loaded it into QGIS to see what these perimeters would look like on a map of California. Using QGIS, she methodically pickedthrough 20,000 rows of data to search for issues, such as our year column being a text column instead of a date column and a year typed as 2106, to get the geodata ready to visualize.

Once the data was cleaned up, Chris processed it with open source tools from MapBox, including their Tippecanoe library, to prepare it for the web. We built the page using MapBox.js and build tools from the NPR App Template. The final page is hosted on s3

We used ColorBrewer to find an accessible and appropriate color scheme for this map. We strive to have all of our data visualizations at the station be color-blindness friendly, which ColorBrewer is a great tool for. 

What was the hardest part of this project?

This was Emily’s first major mapping project, and the first time she tried to clean a database of this size, which posed a few challenges along the way. She knew that creating this map was an important public service, but had to learn along the way how to create it and make it usable for our audience.

The dataset behind this map is large, featuring over 20,000 entries and almost 20 fields when we first got it, which is part of why it was important to create a map like this in the first place. The sheer number of wildfires that have burned in California over the past century is hard to grasp, and we created this map to solve this problem. But that sheer number caused some issues along the way for this relatively new mapmaker.

Emily had to learn how to clean a large database, and was eventually able to cut the number of columns in the database down by 75 percent. But it was still a lot to deal with as she searched for any year entries or fire names that looked irregular, a task she took on in QGIS and Excel. A year later, this is definitely not how she would choose to clean a database.

The reasons that this map was a challenge to make are the same reasons displaying it is an important public service. Cal Fire’s geodatabase of fire perimeters is huge and unwieldy for our audience members to ever try to sift through. By making this information accessible in a visual format, we’ve made it possible for our community to understand and discuss this information.

What can others learn from this project?

This project is a testament to the power of maps to add important context to breaking news events. Our community members were able to browse this map and learn about the history of fires in areas that had recently burned, such as Paradise and Redding, to find out new things about the wildfire news that has consumed California for the past few years. It was fascinating to watch our audience discover new things through this map, like that the Camp Fire was fairly small, though incredibly destructive, and that certain areas have not burned like the rest of the state has.

This data was hiding in plain sight on the Cal Fire website, but no one had taken the step to make it accessible to the public before we created this map. By using data that was already publicly and freely available to create an interactive map, we made it possible for our audience to sift through it and learn about their state in the wake of a devastating fire season.

This project is also a great example for other journalists of how important it is to talk to the person who manages the database that you’re using. Through long conversations with Cal Fire’s Dave Passovoy, we were able to openly and plainly explain what this map does — and does not — show. This meant that when our community members had questions for us about why certain fires they remember were not included, we were able to explain to them that, while this database is incredibly extensive, it is not a 100% complete database of every fire that has burned in this time period. Our conversations with Passovoy were a key part of making this project accurate and informative for our audience.

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