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Normalizing the pandemic: exploring the
cartographic issues in state government COVID-19
Aaron M. Adams, Xiang Chen, Weidong Li & Chuanrong Zhang
To cite this article: Aaron M. Adams, Xiang Chen, Weidong Li & Chuanrong Zhang (2023)
Normalizing the pandemic: exploring the cartographic issues in state government COVID-19
dashboards, Journal of Maps, 19:1, 1-9, DOI: 10.1080/17445647.2023.2235385
To link to this article: https://doi.org/10.1080/17445647.2023.2235385
© 2023 The Author(s). Published by Informa
UK Limited, trading as Taylor & Francis
Group on behalf of Journal of Maps
Published online: 27 Jul 2023.
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Normalizing the pandemic: exploring the cartographic issues in state
government COVID-19 dashboards
Aaron M. Adams
, Xiang Chen
, Weidong Li
and Chuanrong Zhang
Department of Geography, University of Connecticut, Storrs, CT, USA;
UConn GIS Health Lab at Connecticut Children’s, Hartford, CT, USA;
Institute for Collaboration on Health, Intervention, and Policy (InCHIP), University of Connecticut, Storrs, CT, USA;
Environmental Sciences and Engineering, University of Connecticut, Storrs, CT, USA
Government agencies have utilized Web Geographic Information Systems (GIS) dashboards to
collect and disseminate spatial information on COVID-19. However, not all maps on these
dashboards adhere to established cartographic principles. This article explores the extent of
the cartographic issues by surveying state governments’oﬃcial COVID-19 websites in the
United States on February 11, 2021. The results indicate that out of the ﬁfty states, thirty-
one (62.0%) incorrectly used unnormalized data in choropleth maps, sixteen (32.0%) used
normalized data, and three (6.0%) did not employ choropleth maps. Among states using
normalized data correctly, we identiﬁed other cartographic problems, including
inappropriate data class divisions and suboptimal enumeration units. As dashboards serve
as authoritative sources for health information, issues in map creation can inﬂuence public
perception of the health crisis. These ﬁndings underscore the need for map standards to
ensure the accuracy and reliability of health information in the Web GIS era.
Received 6 November 2022
Revised 28 April 2023
Accepted 26 June 2023
COVID-19; choropleth; web
GIS; dashboard; infodemic
The coronavirus disease 2019 (COVID-19) pandemic
has disrupted nearly every aspect of our society and is
responsible for an unprecedented public health cala-
mity in the United States (Centers for Disease Control
and Prevention, 2021). Since the disease information
is organized spatially, governments have employed
geospatial information technology to monitor and
respond to the virus spread in close to real-time
(Kamel Boulos & Geraghty, 2020). With Web Geo-
graphic Information Systems (GIS) that automate
map creation and distribution, public users and auth-
orities can quickly develop, share, and update health
information using web maps quickly enough to make
actionable decisions (Richards, 1999;Zhang et al.,
2015;Zhang & Li, 2005). One of the most widely used
tools to host web maps is the dashboard, a hosted web
service that facilitates interactive visualization of spatial
and non-spatial data (Dong et al., 2020;Griﬃn, 2020).
After the initialization of the COVID-19 dashboard by
Johns Hopkins University (Dong et al., 2020), all ﬁfty
United States state governments created their own
dashboards to enhance pandemic surveillance and
facilitate health communication. Dashboards became
the default method for communicating relevant infor-
mation involving the pandemic with the general public,
and each state made diﬀerent design decisions
(Geraghty & Artz, 2022).
Although the COVID-19 dashboard is considered
‘the most striking cultural artifact’of the pandemic
(Everts, 2020), considerable issues arise as they do
not always follow cartographic principles (Adams
et al., 2020). In this study, we observed that the domi-
nant map type used in dashboards is the choropleth
map, which is a thematic map type using the intensity
of colors to correspond to data values within spatial
enumeration units (Dent, 1990;Tobler, 1973). Choro-
pleth maps are one of the most popular thematic map
types, and some cartographic principles have been well
established to ensure their proper use, such as data
normalization and map symbology principles (Brewer
& Pickle, 2002;Harrower & Brewer, 2003;Jenks, 1963;
Jenks & Caspall, 1971). However, dashboard develo-
pers, including those employed by an authoritative
agency, may not have the essential training to comply
with these principles (Harrower & Brewer, 2003;Juer-
gens, 2020;Lan et al., 2021;Plewe, 2007).
One prevailing cartographic issue in choropleth-
based dashboards is the failure to use normalized data
for mapping –that is, using a relative value (e.g. infec-
tion rates) rather than an absolute value (e.g. cases of
infection) (Adams et al., 2020;Engel et al., 2022;
© 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of Journal of Maps
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which
permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The terms on which this article has been
published allow the posting of the Accepted Manuscript in a repository by the author(s) or with their consent.
CONTACT Xiang Chen firstname.lastname@example.org Department of Geography, University of Connecticut, Storrs, CT 06269, USA; UConn GIS Health Lab
at Connecticut Children’s, Hartford, CT 06106, USA
This article has been corrected with minor changes. These changes do not impact the academic content of the article.
JOURNAL OF MAPS
2023, VOL. 19, NO. 1, 2235385
Kronenfelda & Yoo, 2020). Violating this principle may
disguise spatial patterns due to comparing absolute
values in diﬀerent sizes of enumeration units (Dent,
1990;Krygier & Wood, 2005;Monmonier, 2018;Rezk
& Hendawy, 2023). In the case of the COVID-19 pan-
demic, research has shown that choropleth maps that
show only totals may change people’s perception of
the pandemic (Engel et al., 2022). Therefore, it is rec-
ommended not to use totals in a choropleth map
(Adams et al., 2020). If totals need to be depicted,
other map symbolizations, such as proportional sym-
bols, area cartograms, or dot density, may be used
(Brewer, 2016;Dent, 1990;Zhang, 2020). While it is
possible to ﬁnd examples in the literature where a chor-
opleth map showing totals is appropriate, that same lit-
erature recommends considering graduated symbols in
these cases (Krygier & Wood, 2005).
Figure 1, created from available data on the Centers
for Disease Control and Prevention (CDC)’s COVID-
19 website on May 28, 2022, demonstrates why this mat-
ters with two choropleth maps displaying the samecase
data (Centers for Disease Control and Prevention,
2022). Figure 1(a) shows the total cases of infection by
state, and Figure 1(b) shows infection rates per
100,000 population. As shown in Figure 1(a), Califor-
nia, Florida, New York, and Texas, all have the most
overall cases. There is no coincidence that these four
states also have the largest population in the US, and
Figure 1(a) reﬂects this pattern (Census Bureau,
2022). Figure 1(b) shows the infection rate per
100,000 people, which better facilitates comparisons
among states with small and large populations. Thus,
using an unnormalized map may mislead the public
or decision-makers about the severity of the pandemic;
for example, North Dakota’s high infection rate is only
unveiled in the normalized map (Figure 1(b)).
While this cartographic bias has been documented
in the literature, it has not been well recognized by
most public health professionals and map readers.
For example, while the CDC has switched to publish-
ing normalized case data, it still uses choropleth maps
to show total cases well into the COVID-19 pandemic
(Centers for Disease Control and Prevention, 2021,
2022). While other reviews of dashboards have looked
at the issue and others, including visualizations
besides maps and the frequency of updates (Clarkson,
2023;Fareed et al., 2021;Kronenfelda & Yoo, 2020),
they may not contain data for the entire duration of
the pandemic due to the dynamic nature of web maps.
To this end, this paper aims to articulate the carto-
graphic issues in the COVID-19 dashboards published
by all ﬁfty state governments in the United States.
Speciﬁcally, on February 11, 2021, we examined
whether state governments employed a choropleth
map or another map form for publishing COVID-19
case data. Then, we identiﬁed if these oﬃcial web
maps followed fundamental cartographic principles,
including data normalization, number of classes, color
schemes, and enumeration unit selection. On April 8,
2023, following the United States Senate vote to end
the pandemic, we returned to each Uniform Resource
Locator (URL) to determine the number of states still
hosted the COVID-19 dashboards. This review can
serve as a partial record of how the state governments
of the United States portrayed spatial data during the
COVID-19 pandemic for future researchers. Even-
tually, we hope eﬀorts can be made to improve the con-
sistency and accuracy of health information delivery.
2. Methods and results
To evaluate the extent of the cartographic issues in
COVID-19 maps, we identiﬁed all ﬁfty states’oﬃcial
websites where case data were published in terms of
a dashboard or other types of web maps (Table 2).
We excluded Puerto Rico, Guam, Washington D.C.,
Figure 1. (a) Total infections by state and (b) infection rates in terms of cases per 100,000 people by state. Case data were derived
from the CDC as of May 28, 2022. Class breaks were created using Jenks natural breaks in ArcMap, and labels are rounded to two
signiﬁcant digits for simplicity.
2A. M. ADAMS ET AL.
and other parts of the United States not within state
boundaries to limit the study to comparable adminis-
trative units. We then recorded the types of thematic
maps used on the websites, mainly choropleth maps
and proportional symbol maps (i.e. maps using diﬀer-
ent sizes of circles). If a choropleth map was used, we
checked if the cartographers employed normalized
data (e.g. infection rates) or inappropriately used
unnormalized data (e.g. total cases). We recorded
dashboard URLs along with the data collection,
which took place on February 11, 2021.
As Table 1 illustrates, all states employed certain
forms of COVID-19 dashboards to visualize case
data. Forty-seven states (94.0%) used choropleth
maps, while two states (4.0%), Texas and Wyoming,
used proportional symbol maps. The state of Nebraska
had a general reference map but lacked any form of
thematic map related to COVID-19 cases, with its
website indicating that a map was under production.
Colorado was the only state employing both choro-
pleth and proportional symbol maps.
Figure 2 visualizes the ﬁndings by state. We found
that thirty-one states (62.0%) used unnormalized data
in their choropleth maps in at least one map on their
dashboard, sixteen states (32.0%) rigorously stuck to
normalized data in their choropleth maps, and three
states (6.0%) did not employ choropleth maps. We
observed that at least eleven states, including Alaska,
Alabama, Arizona, Hawaii, Indiana, Michigan,
Mississippi, North Carolina, North Dakota, West Vir-
ginia, and Wisconsin, employed choropleth maps
showing both normalized and unnormalized cases,
which we recorded as using unnormalized choropleth
maps. We also found that the CDC had both normal-
ized and unnormalized data on its web maps (Centers
for Disease Control and Prevention, 2021). We
acknowledge that as dashboards often have multiple
visualizations, we may have missed a map that was
either normalized or unnormalized. Such an omission
would increase the number of states using both but
not decrease the scale of the normalization issue.
These ﬁndings demonstrate that the problem of mis-
using choropleth maps to visualize total COVID-19
cases was widespread.
To investigate further, we separately evaluated the
three categories of normalized choropleth, not choro-
pleth, and unnormalized choropleth. For the sixteen
states that mapped normalized data only, we further
examined their normalization methods. This follow-
up evaluation identiﬁed if other cartographic prin-
ciples regarding map symbology in a thematic map
were followed, such as the number of classes, color
schemes, and enumeration units. Table 2 shows the
results: (1) the most popular normalization method
was a ratio of cases in an enumeration unit (n= 14,
87.5%); only two states (12.5%) employed diﬀerent
normalization methods: California was based on a 7-
day risk level, and South Dakota was based on the
Figure 2. Data normalization status on state COVID-19 dashboards by state.
JOURNAL OF MAPS 3
Table 1. Thematic map types and data normalization status on state COVID-19 dashboards.
State Map type
choropleth maps Variable(s)
(low to high) Enumeration unit
Choropleth Yes Total cases 7 Blue County
Choropleth Yes Total cases Continuous Red Borough/Census
Choropleth Yes Total cases No data Red County
Arkansas Choropleth Yes Total Cases Continuous Blue County
California Choropleth No Risk level (based on 7-day
4 Yellow to purple County
No Cases per 100,000 population Continuous Blue County
Connecticut Choropleth No Cases per 100,000 population 2 Grey to red Town
Delaware Choropleth No 7-day cases per 100,000
6 Blue Zip Code
Florida Choropleth Yes Total cases No data Yellow to Blue County
Georgia Choropleth No 14-day cases per 100,000
Continuous Yellow to Red County
Choropleth Yes 14-day total cases 5 White to orange.
Idaho Choropleth Yes Total cases No data White to orange County
Illinois Choropleth Yes Total cases No data Blue Zip code
Choropleth Yes Total cases No data White to orange County
Iowa Choropleth No 14-day cases per 100,000
population / 7-day cases per
5 Blue County
Kansas Choropleth Yes Total cases No data Blue County
Choropleth No 7-day cases per 100,000
4 Green to red County
Louisiana Choropleth Yes Total cases 4 Blue Census Tract
Maine Choropleth Yes Total cases 4 Pink Zip Code
Maryland Choropleth Yes Total cases 3 Blue County
Massachusetts Choropleth Yes Total cases 5 Blue County
Choropleth Yes Total cases 5 Blue County
Minnesota Choropleth Yes Total cases 7 Blue County
Choropleth Yes 7-day cases per 100,000
5 Blue County
Missouri Choropleth No Cases per 100,000/7-day cases
per 100,000 population
Continuous Red to orange Jurisdiction
(Appears to be
Montana Choropleth Yes Total active cases 4 Blue County
Nebraska Reference map N/A N/A N/A N/A County
Nevada Choropleth No Cases per 100,000 population 6 Blue County
Choropleth Yes Total cases 6 Red to orange.
New Jersey Choropleth Yes New daily cases 7 Blue County
New Mexico Choropleth Yes Total cases Continuous Green County
New York Choropleth Yes Total cases 7 Orange County
Choropleth Yes Total cases 5 Blue County and Zip
Choropleth Yes Total cases No data Red County
Ohio Choropleth Yes Total cases No data Blue County
Oklahoma Choropleth Yes Total cases/total deaths/total
Continuous Yellow Red
Oregon Choropleth No Cumulative cases divided by
5 Blue County
Pennsylvania Choropleth No Cases per 100,000 population 5 Red County
Rhode Island Choropleth No Cases per 100,000 population 6 Yellow to blue Geographic Area or
South Carolina Choropleth No Cases per 100,000 population 5 Blue County
South Dakota Choropleth No Community spread (totals) 3 Blue County
Tennessee Choropleth No Positive tests per 100,000
Continuous Blue and red County
N/A Total Cases Continuous N/A County
Utah Choropleth No 14-day case rate per 100,000
7 Yellow to red County
Vermont Choropleth Yes Total cases in the past 14 days No Data blue County
Virginia Choropleth Yes Total cases 6 blue County
Washington Choropleth Yes Total cases 6 Blue County
Choropleth Yes Total cases in past 7 days No data Blue County
Choropleth Yes Total cases 4 Grey County
NA Total cases Continuous N/A County
Indicates a state where we observed both normalized and unnormalized choropleth maps.
4A. M. ADAMS ET AL.
community spread rates (2) We found that the
majority of states with normalized choropleths on
their dashboards (n= 12, 75.0%) employed discrete
class breaks, while four of these states (25.0%) used a
continuous color scheme. Choosing map symbology
is more ﬂexible than the need for data normalization
but still demands scrutiny from a cartographic per-
spective (Monmonier, 2018). Generally, the literature
suggests using discrete class breaks over continuous
color schemes for making a thematic map, as it is
easier to discern the diﬀerence between data values
(Brewer & Pickle, 2002;Dobson, 1973;Krygier &
Wood, 2005). (3) When mapping with discrete class
breaks, a general rule is to have no less than three
and no more than seven classes best to distinguish
classiﬁed data values (Harrower & Brewer, 2003).
This rule was followed by ten (91.7%) of the eleven
states mapping only normalized data and discrete
class breaks, with most maps having ﬁve classes. (4)
In terms of color hues, seven of the states mapping
only normalized data (43.8%) employed a cold color
hue (e.g. green, blue, and purple), ﬁve (31.3%)
employed a warm color hue (e.g. red, orange, yellow),
and four (25.0%) had a mixed use of cold and warm
colors. (5) For enumeration units, twelve (75.0%)
used county, Delaware used ZIP codes, Connecticut
and Rhode Island used local enumeration units such
as town or municipality, and Missouri used ‘Jurisdic-
tions,’which upon inspection appeared to correspond
to the county boundaries.
The choice of enumeration unit is critical. Due to
the modiﬁable aerial unit problem (MAUP), diﬀerent
ways of subdividing an area can inﬂuence the ﬁnal
aggregate values (Chen et al., 2022). Counties in
many states are administrative units where policy is
made. In some smaller states, like Connecticut and
Rhode Island, counties are often ignored in favor of
smaller administrative units, such as towns (Chen
et al., 2021). These smaller units allow for ﬁner-scale
analysis. ZIP codes, like towns, are also generally smal-
ler than counties; however, their use in epidemiological
mapping is controversial (Chen et al., 2022). ZIP codes
are often discontinued or modiﬁed, do not cover the
entire United States, and their representation as poly-
gons is often not representative of what they cover
(Grubesic & Matisziw, 2006). Therefore, ZIP codes
for the analysis of health data should be avoided, if
possible in favor of census tracts or another more
meaningful enumeration unit, and used cautiously in
consideration of their limits only when unavoidable
(Chen et al., 2022;Grubesic & Matisziw, 2006).
Next, we reviewed the unnormalized maps of the
thirty-one states mapping totals in choropleths to see
if the state dashboards followed other cartographic
principles regarding map symbology. Below are our
ﬁndings: (1) the most mapped variable was cumulative
cases per enumeration unit (n= 25, 80.6%), two states
(6.5%) mapped total cases in 7-day windows, and two
states mapped total cases in 14-day windows. New Jer-
sey mapped total daily cases, and Montana mapped
‘total active cases.’(2) We found that the majority of
states with unnormalized choropleths on their dash-
boards (n= 17, 54.0%) employed discrete class breaks.
In comparison, four states (12.9%) used a continuous
color scheme. As previously stated, the general consen-
sus is that a discrete color scheme may be more easily
understood than a continuous one. We have no data
on class breaks for ten (32.3%) of these states due to
missing legends. (3) All seventeen states employing dis-
crete class breaks used between three and seven classes,
with most maps using ﬁve class breaks, all aligning with
the categorizing pricinple of using 3–7classes.(4)In
terms of color hues, twenty states (64.5%) employed a
cold color hue (e.g. green, blue, and grey), ten states
(32.2%) employed a warm color hue (e.g. red, orange,
yellow), and one state (3.2%) had a mixed use of cold
and warm colors. (5) As for enumeration units, twenty
(80.6%) used county, three (9.6%) used ZIP codes, New
Hampshire used local enumeration units of town, and
Alaska used the local unit of ‘Borough/Census Area.’
North Carolina had both county and ZIP codes avail-
able as options for users to map the case data; however,
as the county was the default visualization, we counted
as using them. One state, Louisiana, used census
tracts in their published maps. As census tracts are
smaller than counties, used throughout the United
States, and created with consideration of human popu-
lations, this choice is highly in line with recommen-
dations in the literature. Surprisingly, among all 50
states, only Louisiana created maps using census tracts
at this point in the pandemic.
For the three states that did not use choropleth
maps on their dashboards (i.e. Nebraska, Texas, and
Wyoming), all mapped using counties. Texas and
Wyoming employed continuous class breaks for
their proportional symbols, which were blue circles.
Nebraska’s map did not show COVID-19-related
data at the time of the survey.
On April 8, 2023, nine days after the United States
Senate voted to end the COVID-19 emergency
declaration, we reviewed the list of URLs and dash-
boards we used in this study. First, we conﬁrmed
that the CDC and Prevention COVID-19 data tracker
we based Figure 1 on still allowed users to view chor-
opleth maps displaying total cases; however, a normal-
ized option still exists, as previously observed (Centers
for Disease Control and Prevention, 2021). Next, we
found that thirteen (26%) of previously identiﬁed
state dashboard URLs no longer led to a publicly
facing dashboard (Table 2). Five enforced a sign-in
procedure for map viewing, while the others were una-
vailable. It is likely that as time progresses, more of
these links will no longer function, contiributing to a
phenomenon known as link rot (Klein et al., 2014).
JOURNAL OF MAPS 5
3. Discussion and conclusion
Since the outbreak of the COVID-19 pandemic, Web
GIS technologies, particularly dashboards, have pro-
vided unprecedented opportunities for sharing health
information. Choropleth maps are overwhelmingly
favored to visualize COVID-19 case data in these dash-
boards (Mooney & Juhász, 2020). Unfortunately, our
ﬁndings reveal that more than half of the states did not
rigorously follow fundamental cartographic principles,
such as data normalization, to create thematic maps.
Even among those states that mapped with appropriate
data, we identiﬁed other cartographic issues, such as
less-than-ideal numbers of classes, color schemes, and
inappropriate choice of enumeration units. These
ﬁndings raise serious concerns regarding Web
mapping as they serve as an authoritative outlet for
delivering health information. The lack of adherence
Table 2. Availability of the URLs for state COVID-19 dashboards.
URL at the time of the survey
(February 11th, 2021)
URL availability on follow-up
(April 8, 2023)
Arkansas https://experience.arcgis.com/experience/c2ef4a4fcbe5458fbf2e48a21e4fece9 No
California https://covid19.ca.gov/state-dashboard/ Yes
Colorado https://covid19.colorado.gov/data Yes
Connecticut https://portal.ct.gov/Coronavirus/COVID-19-Data-Tracker Yes
Delaware https://coronavirus.delaware.gov/ Yes
Florida https://experience.arcgis.com/experience/96dd742462124fa0b38ddedb9b25e429 No
Georgia https://dph.georgia.gov/covid-19-daily-status-report Yes
Illinois https://www.dph.illinois.gov/covid19/covid19-statistics No
Indiana https://www.coronavirus.in.gov/2393.htm Yes
Iowa https://coronavirus.iowa.gov/pages/case-counts No
Kansas https://www.coronavirus.kdheks.gov/160/COVID-19-in-Kansas Yes
Louisiana https://ldh.la.gov/Coronavirus/ Yes
Maine https://www.maine.gov/dhhs/mecdc/infectious-disease/epi/airborne/coronavirus/data.shtml Yes
Maryland https://coronavirus.maryland.gov/ Yes
Massachusetts https://www.mass.gov/info-details/community-level-covid-19-data-reporting Yes
Michigan https://www.michigan.gov/coronavirus/ Yes
Minnesota https://www.health.state.mn.us/diseases/coronavirus/situation.html Yes
Mississippi https://msdh.ms.gov/msdhsite/_static/14,21882,420,873.html No
Missouri https://showmestrong.mo.gov/public-health-county/ Yes
Nebraska https://experience.arcgis.com/experience/ece0db09da4d4ca68252c3967aa1e9dd/page/page_0/ No
Nevada https://nvhealthresponse.nv.gov/ Yes
New Jersey https://www.nj.gov/health/cd/topics/covid2019_dashboard.shtml Yes
New Mexico https://cvprovider.nmhealth.org/public-dashboard.html Yes
New York https://covid19tracker.health.ny.gov/views/NYS-COVID19-Tracker/NYSDOHCOVID-19Tracker-Map?%
North Carolina https://covid19.ncdhhs.gov/dashboard Yes
North Dakota https://www.health.nd.gov/diseases-conditions/coronavirus/north-dakota-coronavirus-cases Yes
Ohio https://coronavirus.ohio.gov/wps/portal/gov/covid-19/dashboards/overview Yes
Oklahoma https://looker-dashboards.ok.gov/embed/dashboards/44 No
Oregon https://experience.arcgis.com/experience/ﬀf9f83827c5461583cd014fdf4587de No
Pennsylvania https://www.health.pa.gov/topics/disease/coronavirus/Pages/Cases.aspx Yes
Rhode Island https://ri-department-of-health-covid-19-data-rihealth.hub.arcgis.com/ Yes
South Carolina https://scdhec.gov/covid19/sc-testing-data-projections-covid-19 No
South Dakota https://doh.sd.gov/COVID/Dashboard.aspx Yes
Tennessee https://www.tn.gov/health/cedep/ncov/data/maps.html Yes
Utah https://coronavirus.utah.gov/case-counts/ Yes
Vermont https://www.healthvermont.gov/covid-19/current-activity/vermont-dashboard Yes
Virginia https://www.vdh.virginia.gov/coronavirus/coronavirus/covid-19-in-virginia-cases/ Yes
Washington https://www.doh.wa.gov/Emergencies/COVID19/DataDashboard#dashboard Yes
West Virginia https://dhhr.wv.gov/COVID-19/Pages/default.aspx Yes
Wisconsin https://www.dhs.wisconsin.gov/covid-19/data.htm Yes
Indicates a dashboard URL now points to an ArcGIS Online sign-in page, and thus may still exist there but be unavailable.
6A. M. ADAMS ET AL.
to cartographic principles in map creation could unex-
pectedly mislead public perception of the pandemic’s
impact (Engel et al., 2022;Geyer & Lengerich, 2023). If
these dashboards were used to assist policymakers,
there is a possibility that a biased epidemiological pat-
tern arising from the maps could have a lasting policy
impact. This review helps to showcase the extent of
these problems as part of the infodemic surrounding
On the other hand, we see positive changes in the
creation of dashboards. For instance, while mapping
totals, the Florida dashboard included a note to the
user that ‘comparison of counties is not possible
because case data are not adjusted by population’
(Florida Department of Public Health, 2021). Simi-
larly, Connecticut initially used unnormalized data
in its dashboard but later switched to normalized
data in its latest version (Adams et al., 2020).
Beyond normalizing data in choropleth maps,
many other methods could be employed to improve
the interpretation of epidemiological data, such as
the cartogram, to show the severity of a health out-
come, where the areal unit is altered proportionally
to the population density aﬀected (Roth et al., 2010;
Tobler, 2004;Zhang, 2020). A complementary
approach when using dynamic web maps is to incor-
porate additional information (such as total cases
and total population) in a pop-up window to present
a more comprehensive view of the health data when
a user clicks on an enumeration unit (Thomas et al.,
2022). Similarly, other visualization methods, such as
dot density maps, hot spot maps based on Getis Ord
Gi* statistic, and relative risk cluster maps created
using Poisson space–time scan statistic, can also be
employed (Dent, 1990;Desjardins et al., 2020;Getis
& Ord, 1992). These visualization and statistical tech-
niques can open new avenues to displaying epidemio-
logical data from multifaceted perspectives without
using a choropleth to display absolute values.
This article focuses on observing choropleth maps
and whether they adhere to established cartographic
conventions on United States State government
oﬃcial dashboards. Our ﬁndings are consistent with
other studies that have identiﬁed widespread misuse
of choropleths throughout the pandemic (Adams
et al., 2020;Engel et al., 2022;Everts, 2020;Kronen-
felda & Yoo, 2020). With this article, we hope that
public health agencies may take the necessary steps
to monitor how data are collected (Tao et al., 2020),
comply with map-making principles, and integrate
other important demographic metrics, such as age
and sex, when making maps (Kontis et al., 2020).
Importantly, we suggest that health professionals, pol-
icymakers, and cartographers should be included in
the discussion when constructing these public-facing
web maps (Plewe, 2007;Rushton et al., 2000). These
combined eﬀorts may help improve health
communication in future health crises as we are nor-
malizing life with this pandemic.
All ﬁgures were produced using ESRI ArcMap 10.7.1.
We thank Adam Gallaher, Ashley Benitez Ou, Dr. Debs
Ghosh, and Rich Mrozinski for supporting data collection
for this research.
No potential conﬂict of interest was reported by the author(s).
This research was supported by pilot grant funding from the
Institute for Collaboration on Health, Intervention, and Pol-
icy (InCHIP) at the University of Connecticut.
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