Detailed Precinct Election Results: Trump v. Clinton Mapped Two Ways (Puget Sound, Part 1)

What’s the best way to map election results? I’m still trying to figure that out, but since election results have been finalized by Washington State it’s a good time to try and figure it out.

When mapped by the media, election returns are typically illustrated at the county level. Counties are often shaded by the percentage of the vote received by a particular candidate within a given county. The November 8th election is no different. More detailed results dig down to the precinct level and use a similar methodology to show the strength of support for a candidate in percentage terms. We don’t see a lot of precinct-level maps that span counties (Seattle Times did accomplish this for initial Sound Transit 3 ballot returns), partly because of the decentralized nature of the election process — there is no database of GIS files containing precinct shapes for all counties in Washington that is kept up to date…

In any case, spatially larger and more rural districts appear to have a stronger impact on the results than they actually do with the typical way that election results are presented. This is clear at the national and local level.

To solve this problem, folks often use cartograms, which reshape districts, counties, precincts, etc., to show their size in population or voters rather than their geography. KUOW recently did this for 2016 presidential election results in a bluntly titled piece, “This election map is a lie. So we made new ones.” Take a look at their cartogram:


This tells you a little bit more about Washington — where the most voters are located and which counties voted strongest for Clinton and Trump. But the counties lose their shape and you can’t really tell what is where. An alternative approach involves shading counties and precincts based on their voter density.

In mapping the presidential election results, I’ve tried to add detail across the region with precinct results while taking into account the density of precincts. As it turns out, there is no perfect way to map election results and to fully understand what’s happening, we need to view multiple maps, side by side.

These maps are a work in progress, as standardizing across different shapefiles and tabulated precinct results has proved difficult and time consuming. Not all precincts are perfectly matched yet and there are some gaps. Let’s have a look.

First, a traditional map with precinct level results that spans nearly all of the counties surrounding Puget Sound (partly because it was easier to find up-to-date shape files in these areas).  This is the first election results map with this level of detail I have seen for our region:percentvotingclintonWhat do we see? It looks like Trump voters are everywhere! Large precincts in more rural and suburban areas skew the visual so that it looks like many areas had large numbers and moderate (here I mean only more than 50%) support for Trump. In Seattle, you see high percentages of each precinct voting for Clinton (Surprising or no? No). Viewing the map this way is interesting, but may actually be more problematic than looking at just county results, as it looks more red than blue in and area like Pierce County, even though the majority of voters their voted for Clinton. Let’s have another go at this.

In this second approach, I’ve taken the same precincts, shaded them red or blue depending on whether there were more votes for Trump or Clinton, and added a transparency layer for each precinct that varies based on the density of voters within that precinct.puget-sound-voters

Here, we get a very different picture. We see where the concentrations of voters are, in the dark red and dark blue areas, and areas with lower density are faded so as not to skew the map. As opposed to the first map, this shows where larger concentrations of Trump voters are — in Pierce County, near Puyallup. An improvement for sure. But what’s missing? Whether or not these precincts voted overwhelmingly for Trump. Comparing the two maps, we can so that this is not the case; while precincts south of Puyallup voted for Trump, they did not do so en masse. It would be great to see such analysis elsewhere, and for the entire state!

Three dimensional maps are a useful fix for the issues outlined above, making it possible to show the concentration of voters and what percentage voted for a given candidate, while keeping the general shape of the precinct, county, or other geography.

(Full versions of maps can be downloaded here and here).

Some technical notes. In working to create these two maps I have run up again a few major roadblocks that others should address:

  • Many counties do not offer downloads of their GIS shape files for election precincts. Ideally, this could be centralized at the state level.  In fact, it is, but only circa 2010 as the result of the 2010 census & redistriciting process. The precincts have changed in some areas, and names do not align, making it difficult to link tables together.
  • Not all counties provide precinct-level results. Typically these are more rural, lower population counties, and likely have fewer resources. Overtime I’m sure this will improve and I was surprised how many counties are providing this detail. Still, it is difficult to find the GIS files of the actual precincts.

visualizing (mapping) the depth & elevation of Puget Sound

Having survived the “greatest storm since…” that wasn’t, I used my unexpected access to electricity and the internet to develop a few maps of Puget Sound. My experience with rasters is limited, at best, but so many visually-stunning QGIS map examples around the web have piqued my interest over the last few months. Also, QGIS makes working with rasters extremely easy and intuitive.


For this mapping exercise, I downloaded a wonderful raster from the UW’s School of Oceanography.  Playing around with this was pretty fun. The first map ‘depth’ shows where Puget Sound is deepest (the darker areas). With these colors, the map almost looks like a watercolor painting.



Getting more creative and interested in lower Puget Sound near the Nisqually Delta, I came up with the following intriguing visualization:

pugetlowI like how this map shows the lower Puget Sound meeting land, slowly disappearing as the elevation gains. Here, everything above 400 feet is white, to focus on the contrast at lower elevations near and below sea level. Notably, everything below 800 feet is also a very dark blue.

With these parameters (see table of contents in map), the Rainier Valley really pops out in South King County. The Port of Tacoma is also interesting when viewed through this lens.

View the full hi-res map here.



Mapping Washington’s 7th Congressional District Primary Results

Let’s take a quick tour through local electionland. The race to replace retiring Congressman Jim McDermott is on — it’s Pramila Jayapal v. Brady Walkinshaw in November. Jayapal made a statement with her commanding victory in the August 2nd primary, winning 43% of the vote. Walkinshaw squeezed in second with 21%, besting Joe McDermott’s 19%. But you knew that already. You’re hear because you want to see where Jayapal’s support was strongest in this low-turnout primary – right?

For that, we have the final election precinct reports from King County Elections (very useful, thank you KC!). Let’s have a look.

First, in the spirit of democracy, let’s map every vote cast and see how that looks.


Much of Jayapal’s support came in the northern section of this oddly-shaped district. Support appears strong in Capitol Hill as well as in North Seattle and weaker in Magnolia and West Seattle, where there is a flurry of Joe McDermott dots. To see Jayapal’s win more clearly, the following shows the percentage she won in each precinct:

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blockgrp_race | mapping every person in king county and their race with the latest census data

This collection is inspired by this excellent web map, which used 2010 block-level census data to map every person in the country and their race. As that map shows, as well as the one below, many of our cities are still very segregated. Some maps by some folks at UW also recently examined this reality in South Seattle.

The maps below use block group level (larger than census blocks, but the smallest geography the Census Bureau publishes data on in between the decennial census) data on the racial makeup of King County. Using a dot density map is a great way to illustrate the racial makeup of a city, but I have some qualms.  Census geographies vary in their population, and keeping the same scale across a single map (keeping the dots the same size) means that some areas end up with a bucket of dots. It can be especially confusing when a very dense geography is also very diverse, as in South Seattle. To address some of this, I have added a limited amount of transparency to all of the dots, which you can see when you zoom in far enough on the hi-res version.

The data is pulled from the 2010 – 2014 American Communities Survey.

Each dot represents one person, placed at random within each block group.

Let’s take a look at some initial maps.


Explore the full resolution version here.

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There is a lot you can mine from the King County Assessor’s database on parcels, buildings, land values, the quality of some housing, and whether or not there are views of Mt. Rainier. I’ve been working on a map of King County based on the year buildings were initially built. The map includes only residential structures – typically single-family homes, apartment complexes, and condos. It represents the places we live and when they were built.

Darker red areas indicate older housing. Blue areas indicate more recent housing. The lighter colored areas really represent mid-century housing. The map reveals some interesting patterns, some more surprising than others. Let’s take a look.

University District and Surrounding Areas:


Vashon Island:


The island has more of a mix – I was surprised by how much appears to be more recent construction, relative to other areas of the county.

Capitol Hill, Central District, Montlake, Eastlake, Etc.: 

capitol hill.png



This collection of residential parcels in Georgetown really sticks out – surrounded by industry and an airport.

Here’s most of Seattle. The colors blend together, which adds a interesting brick-like look. When viewing the whole city, the map fairly effectively shows Seattle’s historical development patterns. To the east, you can see the development of Bellevue, Kirkland, Mercer Island, and Newcastle, which has come much more recently.


More to come on this front, but wanted to get this new endeavor, nw mapt, started.


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