Source files for https://rpubs.com/aoles/bombs_ors

bombs.Rmd

---
title: "London Blitz Bombs"
author: "Andrzej K. Oleś"
output: html_document
---

```{r config, include=FALSE}
## set up knitr defaults
knitr::opts_chunk$set(eval=TRUE, out.width='100%', out.height='560px')
```

Visualization of the location of the bombs that were dropped on London in the
night of September, 7th, 1940 based on data provided by the Guardian Data Store
& London Fire Brigade Records referenced by the website of the British National
Archives http://bombsight.org.

```{r data_source, message=FALSE, warning=FALSE}
library(googlesheets)

data_url <- "https://docs.google.com/spreadsheets/d/1rL68hnF9bHHg3p72ti_reSvwK12VEdABN5Q7YADXm3I"
data <- gs_read(gs_url(data_url))
```

In order to query openrouteservice you need to set up the API key first, see
`?ors_api_key`. The geocoding takes About 20 minutes because of the API rate
limit of 40 requests per minute.

```{r geocode, eval=FALSE}
library(openrouteservice)

## Takes about 20 min to complete, needs API key set
coordinates <- sapply(data$Location, function(loc) {
  x <- ors_geocode(loc, size = 1)
  x$features[[1L]]$geometry$coordinates
}, USE.NAMES = FALSE)

df <- as.data.frame(t(coordinates))
colnames(df) <- c("lng", "lat")

save(df, file = "df.rda")
```

```{r load_data, include=FALSE}
load("df.rda")
```

```{r leaflet, }
library(leaflet)

leaflet(df) %>%
  addProviderTiles(providers$CartoDB.Positron) %>%
  addCircleMarkers(color = "red",
                   radius = 5,
                   stroke = FALSE,
                   fillOpacity = 0.3) %>%
  setView(-0.1278, 51.5074, 12)
```

df.rda