GGplot

Notes

This is a non-interactive map built with basic ggplot2 functions.

I am using a shapefile-based set of multipolygons for the town outlines.

On the following tabs, I’ve created interactive versions of this same figure using plotly::plot_ly() and leaflet::leaflet().

Plot_ly

Notes

Interactive choropleth with plotly::plot_ly().

I’m using a geojson-based set of polygons for town outlines in this map. Plot_ly() gets the aspect ratio wrong if using the shapefile-based set of multipolygons that I used with ggplot() and ggplotly() maps. I’m not sure why.

Also, the shapefiles are probably higher resolution than needed. Using the lower res geojson polygons saves nearly 3mb on the total file size.

Leaflet

10 Day Average Covid-19 Test Positivity
in Connecticut Towns
for period ending June 24, 2022

Notes

Interactive choropleth via leaflet::leaflet().

Previous plots in this series used multipolygon shapes for towns taken from conventional shape files. I couldn’t get that to work with leaflet and so switched to simple polygons. These were read from geojson files, but I think the crucial difference is multipolygon vs. somple polygons.

I don’t know why the colorscale in the legend is inverted relative to expectations. It’s annoying, but there doesn’t seem to be a way to correct it. A couple of “solutions” I’ve seen proposed on StackOverflow just don’t work.

Leaflet maps don’t provide a “title” feature, as such. Here, I’ve just added the title text above the map. Formatting is by way of the HTML <font> tag. It’s not best practice, but it works.

About the Maps

Covid data used in these maps was compiled by CT Dept. of Public Health through Jun 24, 2022 and accessed through https://data.ct.gov/stories/s/COVID-19-data/wa3g-tfvc/#data-library.

Maps were created by David Braze (davebraze@gmail.com) using R statistical software and released under the Creative Commons v4.0 CC-by license.

You can always find the most current version of this data sketch online at: https://davebraze.github.io/ct-covid-map-examples/.

About the Author

David Braze is a researcher and consultant with a background in linguistics and reading research. He has more than 25 years experience investigating the cognitive foundations of language, literacy, and educational achievement, including 17 years as a Senior Research Scientist at Haskins Laboratories. His research at Haskins, funded by the National Institutes of Health, emphasized the neurobiology of language and reading and applications to education. Dr. Braze consults widely for business, government, and non-profit sectors.

About the Software

All data summaries in this dashboard were produced with the R statistical environment, version 4.1.0. The dashboard itself was made using an Rmarkdown workflow. The following table lists the non-base R packages used in building the dashboard. To see a full citation for a specific package, assuming you have both R and the particular package installed, call (e.g.) citation("dplyr") from the R prompt.