In lmitchell4/earthquake: Functions for Working with Earthquake Data Set

title: "Overview of Earthquake Plots" author: "L. Mitchell" date: "r Sys.Date()" output: rmarkdown::html_vignette vignette: > %\VignetteIndexEntry{Overview of Earthquake Plots} %\VignetteEngine{knitr::rmarkdown} %\VignetteEncoding{UTF-8}

library(earthquake)
library(knitr)
library(dplyr)
library(ggplot2)
library(magrittr)

Timeline Plots

The earthquake package contains functions for creating timeline plots and maps of earthquakes. The eq_timeline function produces a timeline plot built on the ggplot2 library. An example plot is shown below.

eqDataClean <- eq_clean_data("NOAA_earthquakes.txt")
eqDataShort <- eqDataClean %>%
  dplyr::filter(Country %in% c("Mexico","New Zealand") & YEAR >= 2006 & 
                YEAR <= 2010)
eq_timeline(dataset=eqDataShort)

Date is represented on the x-axis, Country is represented on the y-axis, point size reflects the magnitude (based on the field EQ_PRIMARY), and fill color reflects the total number of deaths (based on the field TOTAL_DEATHS). A custom theme with a white background, eqTheme, is automatically applied.

If the optional argument label is set to TRUE, the value of LocalLocation is added to each point as a text label:

eq_timeline(dataset=eqDataShort, label=TRUE)

The optional arguments xmin and xmax can be used to subset the data:

eq_timeline(dataset=eqDataShort, xmin=as.Date("2009-01-01"), xmax=as.Date("2011-01-01"))

The function eq_timeline is designed to make producing these plots easier, but if you want to change the aesthetics arguments or theme, you can use the underlying geoms directly, as shown in the following examples.

ggplot2::ggplot(eqDataShort) +
  geom_timeline(ggplot2::aes(x=DATE, y=Country, fill=TOTAL_DEATHS, size=EQ_PRIMARY))

ggplot2::ggplot(eqDataShort) +
  geom_timeline_label(ggplot2::aes(x=DATE, y=Country, fill=TOTAL_DEATHS, size=EQ_PRIMARY, 
                                   label=LocalLocation))

Compare the two plots below to see how the custom theme EqTheme changes the appearance:

ggplot2::ggplot(eqDataShort) +
  geom_timeline_label(ggplot2::aes(x=DATE, y=Country, fill=TOTAL_DEATHS, size=EQ_PRIMARY, 
                                   label=LocalLocation))

ggplot2::ggplot(eqDataShort) +
  geom_timeline_label(ggplot2::aes(x=DATE, y=Country, fill=TOTAL_DEATHS, size=EQ_PRIMARY, 
                                   label=LocalLocation)) + 
  eqTheme()

Interactive Maps

The function eq_map produces interactive maps using the JavaScript library leaflet (http://leafletjs.com). Running this function will cause a map to open in your default browser. A circle is shown at the epicenter of each earthquake with the circle radius being proportional to the magnitude (based on the field EQ_PRIMARY). The argument annot_col should be the name of a column (as a string) in the dataset. This column is used to generate content for pop-up windows that appear when you click on a circle. The following example shows the date in the pop-up window. Click on any of the blue circles to see the pop-up window.

eqDataMexico <- eqDataClean %>%
  dplyr::filter(Country == "Mexico" & YEAR > 2002)
eq_map(dataset=eqDataMexico, annot_col="DATE")

The function eq_create_label can be used to generate a summary consisting of the earthquake's local location (LocalLocation), magnitude (EQ_PRIMARY), and total number of deaths (TOTAL_DEATHS). In the following example eq_clean_label is used to create a new column in the data set called popup_text, then that column is used in the pop-up window.

eqDataMexico <- eqDataClean %>%
  dplyr::filter(Country == "Mexico" & YEAR > 2002)
eqDataMexico$popup_text <- eq_create_label(eqDataMexico)
eq_map(dataset=eqDataMexico, annot_col="popup_text")