---
title: "Downloading Shape Files for DHS Surveys"
author: "OJ Watson"
date: "2020-02-11"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Downloading shape files for DHS surveys}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

## Overview

`rdhs` can be used to download shape files associated with the DHS surveys. For
example, we can link API responses to their shape files and plot the subnational
estimates using the spatial pacakge `sp`. To do this, we use the new function
`download_boundaries` from `rdhs` to download shape files. 


```r
# load our package
library(rdhs)

# make request
d <- dhs_data(countryIds = "SN",
              indicatorIds = "FE_FRTR_W_A15",
              surveyYearStart = 2014,
              breakdown = "subnational")

# get our related spatial data frame object
sp <- download_boundaries(surveyId = d$SurveyId[1])
```

```
## OGR data source with driver: ESRI Shapefile 
## Source: "/tmp/RtmpkjqL1S/file115c2d9e2d9d/shps", layer: "sdr_subnational_boundaries"
## with 4 features
## It has 27 fields
```

```r
# match our values to the regions
m <- d$Value[match(sp$sdr_subnational_boundaries$REG_ID, d$RegionId)]
sp$sdr_subnational_boundaries@data$Value <- m

# Use sp to plot
sp::spplot(sp$sdr_subnational_boundaries, "Value", main = d$Indicator[1])
```

![](https://github.com/ropensci/rdhs/raw/development/vignettes/boundaries_files/figure-html/normal-1.png)<!-- -->

Or we can use `sf` for our plotting, which offers more user-friendly plotting
options. 


```r
# make request
d <- dhs_data(countryIds = "SN",
              indicatorIds = "FE_FRTR_W_A15",
              surveyYearStart = 2017,
              breakdown = "subnational")

# get our related spatial data frame object
sp <- download_boundaries(surveyId = d$SurveyId[1], method = "sf")
```

```
## Reading layer `sdr_subnational_boundaries' from data source `/tmp/RtmpkjqL1S/file115c5afcf6fd/shps/sdr_subnational_boundaries.dbf' using driver `ESRI Shapefile'
## Simple feature collection with 14 features and 27 fields
## geometry type:  MULTIPOLYGON
## dimension:      XY
## bbox:           xmin: -17.54548 ymin: 12.30127 xmax: -11.35754 ymax: 16.69266
## epsg (SRID):    4326
## proj4string:    +proj=longlat +datum=WGS84 +no_defs
```

```r
# match our values to the regions
m <- d$Value[match(sp$sdr_subnational_boundaries$REG_ID, d$RegionId)]
sp$sdr_subnational_boundaries$Value <- m

# Use ggplot and geom_sf to plot
library(ggplot2)
ggplot(sp$sdr_subnational_boundaries) + 
  geom_sf(aes(fill = Value)) + 
  ggtitle(d$Indicator[1])
```

![](https://github.com/ropensci/rdhs/raw/development/vignettes/boundaries_files/figure-html/sf-1.png)<!-- -->
