---
title: "Introduction to aopdata"
date: "`r Sys.Date()`"
output: rmarkdown::html_vignette
urlcolor: blue
vignette: >
  %\VignetteIndexEntry{Introduction to aopdata}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---
  
```{r, include = FALSE}
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  eval = identical(tolower(Sys.getenv("NOT_CRAN")), "true"),
  out.width = "100%"
)
```

This vignette introduces the **`aopdata`** package.

**`aopdata`** is an R package to download data from the [Access to Opportunities Project (AOP)](https://www.ipea.gov.br/acessooportunidades/en/). The AOP is a research initiative led by the Institute for Applied Economic Research (Ipea) with the aim to study transport access to opportunities in Brazilian cities. 

The **`aopdata`** package brings annual estimates of access to employment, health, education and social protection services by transport mode at a fine spatial resolution for the 20 largest cities in Brazil. The package also brings  data on the spatial distribution of population by sex, race, income and age, as well as the distribution of jobs, schools, healthcare facilities and social assistance reference centers.

Data for 2017, 2018 and 2019 are already available, and cover accessibility estimates by car and active transport modes (walking and cycling) for the 20 largest cities in the country, and by public transport for over 9 major cities. For more information on the [AOP website](https://www.ipea.gov.br/acessooportunidades/en/).


## Installation

You can install `aopdata` from CRAN, or the development version from GitHub.

```{r, message = FALSE, eval = FALSE}
# CRAN
install.packages("aopdata")

# dev version from github
utils::remove.packages('aopdata')
devtools::install_github("ipeaGIT/aopdata", subdir = "r-package")

```

## Overview of the package
The **aopdata** package includes five core functions.

- `read_population()` - Download population data
- `read_landuse()` - Download landuse data
- `read_access()` - Download accessibility estimates
- `aopdata_dictionary()` - Opens aopdata data dictionary on a web browser
- `read_grid()` - Download the H3 hexagonal spatial grid

For a detailed explanations of these functions, check the **vignettes**:

- [Mapping urban accessibility](access_maps.html)
- [Mapping population data](population_maps.html)
- [Mapping land use data](landuse_maps.html)
- [Analyzing inequality in access to opportunities](access_inequality.html)

## Basic Usage

First, you need to load the package.
```{r, message = FALSE, eval = TRUE}
library(aopdata)

```

### Data dictionary

The dictionary of data columns is presented in the documentation of each function. However, you can also open the data dictionary on a web browser by running:

```{r, message = FALSE, eval = TRUE}
# for English
aopdata_dictionary(lang = 'en')

# for Portuguese
aopdata_dictionary(lang = 'pt')
```



### Accessibility estimates

The `read_access()` function downloads accessibility estimates for a given `city`, `mode` and `year`. For the sake of convenience, this function will also automatically download the population and land use data for the cities selected. Note that accessibility estimates are available for peak and off-peak periods for `public_transport`and `car` modes.

```{r, message = FALSE, eval = TRUE}
# Download accessibility, population and land use data
df <- aopdata::read_access(
  city = 'Curitiba', 
  mode = 'public_transport', 
  peak = TRUE,
  year = 2019,
  showProgress = FALSE
  )
```

You many also set the parameter `geometry = TRUE` so that functions return a spatial `sf` object with the geometries of the H3 spatial grid.

```{r, message = FALSE, eval = TRUE}
# Download accessibility, population and land use data
df <- aopdata::read_access(
  city = 'Curitiba', 
  mode = 'public_transport', 
  peak = TRUE,
  year = 2019,
  geometry = TRUE
  )
```


### Population and land use data

In case you are only interested in using the population and land use data generated by the Access to Opportunities Project, you can download these data sets separately. Please note that the population available comes from the latest Brazilian 2010 census, while land use data cna be downloaded for 2017, 2018 or 2019.

```{r, message = FALSE, eval = TRUE}
# Land use data
df <- aopdata::read_landuse(
  city = 'Fortaleza', 
  year = 2019,
  geometry = TRUE,
  showProgress = FALSE
  )

# Population data
df <- aopdata::read_population(
  city = 'Fortaleza', 
  year = 2010,
  geometry = TRUE,
  showProgress = FALSE
  )
```

### Read only spatial grid data

In case you would like to download only the H3 spatial grid of cities in the AOP project, you can use the `read_grid()` function.

```{r, message = FALSE, eval = TRUE}
h3 <- aopdata::read_grid(city = 'Fortaleza', showProgress = FALSE)

```

### Note
In all of the functions above, note that:

- The `city` parameter can also be a 3-letter abbreviation of the city.
```{r, message = FALSE, eval = TRUE}
df <- aopdata::read_access(
  city = 'cur', 
  mode = 'public_transport', 
  year = 2019,
  peak = TRUE,
  showProgress = FALSE
  )

df <- aopdata::read_grid(city = 'for', showProgress = FALSE)
```

- You may also download the data for all cities of the project at once using `city = 'all'`:
```{r, message = FALSE, eval = FALSE}
df <- aopdata::read_landuse(city = 'all', year = 2019)

```

# Acknowledgement 
The R package **aopdata** is developed by a team at the Institute for Applied Economic Research (Ipea), Brazil.

# Citation 

If you use this package in your own work, please cite it as one of the publications below:

**Population and land use data**

- Pereira, Rafael H. M. et al. (2022) Distribuição espacial de características sociodemográficas e localização de empregos e serviços públicos das vinte maiores cidades do Brasil. *Texto para Discussão 2772*. Ipea - Instituto de Pesquisa Econômica Aplicada. Available at http://repositorio.ipea.gov.br/handle/11058/11225

**Accessibility data**

- Pereira, Rafael H. M. et al. (2022) Estimativas de acessibilidade a empregos e serviços públicos via transporte ativo, público e privado nas 20 maiores cidades do Brasil em 2017, 2018, 2019. *Texto para Discussão*. Ipea - Instituto de Pesquisa Econômica Aplicada. 
