class: center, middle, inverse, title-slide # Practical Mapping in R:<br>Lat/Lon plotting & Choropleths ## leaflet, tidycensus, and sf ### John Little ### 2018-10-23 --- exclude: true example of a test slide, not displayed. Next. --- class: middle, center Part of the ### [Rfun](http://rfun.library.duke.edu) Learning Series of Workshops http://rfun.library.duke.edu --- exclude: false class: top, center background-image: url(http://library.duke.edu/data/sites/default/files/datagis/images/data_gis_logo.png) ## Data & Visualization Services ### [library.duke.edu/data](http://library.duke.edu/data) [rfun.library.duke.edu](https://rfun.library.duke.edu/) <br>for slide annotations, keystroke: *p* ??? This is a presenter comment for the presenter mode use 'p' to toggle the presenter mode or '?' or 'h' to toggle the help / key-shortcut options --- ## Prerequisites - 023 Lab Workstations (All packages and versions already installed) - [Intro to R](https://intro2r.library.duke.edu/): Tidyverse, R Notebooks, R Markdown, RStudio - [ggplot2](https://ggplot.library.duke.edu/) ## Background Resources - [Intro2r](https://rfun.library.duke.edu/intro2r/) - [Reproducibility with git & RStudio](https://rfun.library.duke.edu/git/) - [Visualization in R using ggplot2](https://rfun.library.duke.edu/portfolio/ggplot_workshop/) - [DVS learning materials: handouts, guides, data, and videos](http://library.duke.edu/data/news/past-workshops) --- ## Why Make Maps with R - Already comfortable with R and not as familiar with - ArcGIS - QGIS - Tableau - Python --- ## Library Packages used in this Workshop - **`leaflet`** -- creates interactive maps - **`tidycensus`** -- thematic mapping, Census geography (shapefiles), Census data - **`sf`** - [Simple Features Access](https://en.wikipedia.org/wiki/Simple_Features) for R (Open Geospatial & ISO) - `ggplot2` -- especially `geom_sf()` and `facet_wrap()` - `ggmap` -- can quickly generate simple static maps + more - Thematic Mapping - `tmap` - `ggplot2` - `viridis` -- diverging colors, sequential, bucketing colors - `dplyr` (`tidyverse`) See Also [System Info](http://rfun.library.duke.edu/map/software_prereqs.html#packages) --- ## Other GIS and mapping packages Packages of interest but not part of this workshop include... - `rgdal` - `raster` - `maptools` - `argeos` --- class: duke-green, middle, center ## Hands-on --- ## Outline .pull-left[ 1. Georeferencing with lat/lon points and leaflet 1. Choropleth with tidycensus 1. Interactive Thematic Mapping with Simple Features ] .pull-right[ <figure><img src="https://imgs.xkcd.com/comics/heatmap.png"><figcaption> Image Credit: XKCD. <a href="https://xkcd.com/1138/">HeatMap</a></figcaption></figure> ] --- class: center, middle, duke-softblue ## Georeferencing Plotting X/Y Coordinates (latitude/longitude) *leaflet* --- class: center background-image: url(images/xy.png) ## 2012 Starbucks Locations in the Triangle ---  ??? Image Credit: [GAO](https://www.flickr.com/photos/usgao/8269791489/) --- class: center, middle, duke-softblue ## Choropleth Shading areas with a variable *tidycensus* --- background-image: url(images/choropleth_wages.png) --- ## Census - ACS & Decennial Census - Census Geography --- background-image: url(images/decennial_v_acs.jpg) ??? Census slide deck on [ACS](http://slideplayer.com/slide/10535013/) --- background-image: url(images/hierarchy.png) ??? https://www.census.gov/geo/reference/webatlas/ --- background-image: url(images/polygons.png) ## Polygons --- ## Identifying Census Variables - `tidycensus` -- [How To: *Searching for Variables*](https://walkerke.github.io/tidycensus/articles/basic-usage.html#searching-for-variables) - Social Explorer has great documentation with ACS/Decennial Tables and Variable IDs - Example of [Census Bureau TIGER Metadata](https://www2.census.gov/geo/tiger/TIGER_DP/2015ACS/Metadata/STATE_METADATA_2015.txt) file --- class: center, middle, duke-softblue ## Thematic Mapping *tmap* *sf* *ggplot2* --- ## Simple Features - `sf()` - simple features (tidyverse compatible) - `sp()` - spatial polygons (legacy) - To coerce objects: [sf to and from `sp`](https://cran.r-project.org/web/packages/sf/vignettes/sf1.html#conversion-including-to-and-from-sp) - sf will also read rgdal rgeos [documentation](https://cran.r-project.org/web/packages/sf/vignettes/sf1.html#conversion-including-to-and-from-sp) - Shapefiles - `st_read()` - `st_write()` - [sf vingette 2](https://cran.r-project.org/web/packages/sf/vignettes/sf2.html#using-st_read) --- ## Workflow for Thematic Mapping 1. Get Tiger Shapefiles (`tigris`) as simple features (`sf`) 1. Get Data (e.g. BLS Data) - import XLS data (`readxl`) - wrangle data into tidy format (`dplyr`) 1. Join measure to polygon (`tmap::append_data`) 1. Visualize (Fill polygons with variable) - `qtm` - `tmap::tm_shape` - `ggplot2::geom_sf` --- class: middle, duke-green ## Save, Write, Output - `leaflet` and/or `htmlwidgets` can - Read GeoJSON natively - Export a self contained HTML document - Integrate an HTML widget into an R Notebook --- ## Thank You For Attending .pull-left[ ### I am ... - **John Little** - https://johnlittle.info - https://github.com/libjohn #### Schedule Me - [http://v.gd/littleconsult](http://duke.libcal.com/appointment/2695) ### With ... - **Drew Keener** - [library.duke.edu/data/../staff/](https://library.duke.edu/data/about/staff/) ] .pull-right[ ### We are... - Data & Visualization Services - https://library.duke.edu/data - The /Edge, Bostock (1st Floor) #### Walk-in Hours - [Schedule](http://library.duke.edu/data/about/schedule) #### Our Workshops - [Current Workshops](http://library.duke.edu/data/news) - [Past Workshops](http://library.duke.edu/data/news/past-workshops) #### Contact Us - askData@Duke.edu ] --- ## Resources - [Five great charts in 5 lines of R code each](https://www.r-bloggers.com/five-great-charts-in-5-lines-of-r-code-each/) by Sharon Maclis - [TidyCensus](https://walkerke.github.io/tidycensus/) by Kyle Walker - [Using tidycensus and leaflet to Map Census Data](https://juliasilge.com/blog/using-tidycensus/) by Julia Silge - Sharon Maclis - [Mapping in R just got a whole lot easier](https://www.computerworld.com/article/3175623/data-analytics/mapping-in-r-just-got-a-whole-lot-easier.html) - [Introduction to Spatial Data Types in R](https://cengel.github.io/rspatial/2_spDataTypes.nb.html#how-to-do-this-in-sf) by Claudia Engel - DataCamp.com's [Working with Geospatial Data in R](https://www.datacamp.com/courses/working-with-geospatial-data-in-r) by Charlotte Wickham - [Introduction to visualising spatial data in R](https://cran.r-project.org/doc/contrib/intro-spatial-rl.pdf). Lovelace, Cheshire, and Oldroyd - [Simple Features for R](https://r-spatial.github.io/sf/index.html) - [tmap in a nutshell](https://cran.r-project.org/web/packages/tmap/vignettes/tmap-nutshell.html) - [viridis color palettes](https://cran.r-project.org/web/packages/viridis/vignettes/intro-to-viridis.html) - [The Pros & Cons of Choropleth maps](https://viscomvibz.wordpress.com/2012/03/17/the-pros-cons-of-choropleth-maps-blot-maps-patch-maps/) --- ## Image Credits - [GIS Layers](https://www.flickr.com/photos/usgao/8269791489/) - [Decennial v ACS](http://slideplayer.com/slide/10535013/) - [Census Geography](https://www.census.gov/geo/reference/webatlas/) | [PDF](https://www2.census.gov/geo/pdfs/reference/geodiagram.pdf) - [CA Polygons](https://commons.wikimedia.org/wiki/File:California_Geomorphic_Provinces.svg) --- class: center, middle ## Shareable Data, presentation, and handouts <span class="cc"> <!-- Key: a: SA, b: BY, c: CC Circle, d: ND, n: NC, m: Sampling, s: Share, r: Remix, C: CC Full Logo --> C bn </span> [CC BY-NC license](https://creativecommons.org/licenses/by-nc/4.0/)