06-custom-maps.Rmd

---
title: "Custom and Animated Maps"
author: "Angela Li"
date: "2/19/2019"
output: html_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
```

> Tip: Use the `Ctrl-Opt-I` keyboard shortcut to insert a code chunk into your Markdown document.

## Load packages

```{r warning=FALSE, message=FALSE}
library(sf)
library(ggplot2)
library(spData)
library(tmap)
library(magick)
```

## Look at data

```{r}
head(urban_agglomerations)
str(urban_agglomerations)
names(urban_agglomerations)
```

```{r}
tail(urban_agglomerations)
```

Looks like `urban_agglomerations` is a panel-data version of population of global cities, between 1950 and 2030.

## Make a ggplot2 map

```{r}
ggplot(urban_agglomerations) +
  geom_sf()
```
```{r echo=FALSE, warning=FALSE, message=FALSE, results='hide'}
# I had to do this because my spData for some reason was weird, you may not need to do this
library(dplyr)

names(world)
world <- rename(world, geometry = geom)

names(world)
```


```{r}
ggplot(world) +
  geom_sf()
```

```{r}
ggplot() +
  geom_sf(data = world) +
  geom_sf(data = urban_agglomerations)
```

## Move it over to tmap!

### Single custom map

```{r}
tm_shape(world) +
  tm_polygons() +
  tm_shape(urban_agglomerations) +
  tm_dots(size = "population_millions", title.size = "Population (m)", col = "red")
```

### Map with small multiples

```{r}
tm_shape(world) +
  tm_polygons() +
  tm_shape(urban_agglomerations) +
  tm_dots(size = "population_millions", title.size = "Population (m)", col = "red") +
  tm_facets(by = "year")
```

### Map (animated!!)

```{r}
tm <- tm_shape(world) +
  tm_polygons() +
  tm_shape(urban_agglomerations) +
  tm_dots(size = "population_millions", title.size = "Population (m)", col = "red") +
  tm_facets(along = "year", free.coords = FALSE)

tmap_animation(tm, "city-pop-anim.gif", loop = TRUE, delay = 80)
```

```{r}
magick::image_read("city-pop-anim.gif")
```