---
title: "Interacting with geojson API returns"
author: "OJ Watson"
date: "2018-09-24"
output: rmarkdown::html_vignette
vignette: >
%\VignetteIndexEntry{Interacting with geojson API results}
%\VignetteEngine{knitr::rmarkdown}
%\VignetteEncoding{UTF-8}
---
## Overview
The API can return geojson objects, which can be very useful for quickly creating maps of the
DHS indicator data. These are large objects though, and can cause the API to return slowly if
too much data is returned.
In this demonstration we will be using 2 other packages, `leaflet` and `geojson`.
---
```r
# load our package
library(rdhs)
# install other packages
# install.packages("geojson")
# install.packages("leaflet")
```
```r
# make request
d <- dhs_data(countryIds = "SN",
indicatorIds = "FE_FRTR_W_A15",
surveyYearStart = 2014,
breakdown = "subnational",
returnGeometry = TRUE,
f = "geojson")
# convert to sp
m <- geojsonio::as.json(d)
nc <- geojsonio::geojson_sp(m)
# plot using leaflet
pal <- leaflet::colorNumeric("viridis", NULL)
leaflet::leaflet(nc[nc$IndicatorId=="FE_FRTR_W_A15",]) %>%
leaflet::addTiles() %>%
leaflet::addPolygons(stroke = FALSE, smoothFactor = 0.3, fillOpacity = 1,
fillColor = ~pal(log10(Value)),
label = ~paste0(CharacteristicLabel, ": ", formatC(Value, big.mark = ","))) %>%
leaflet::addLegend(pal = pal, values = ~log10(Value), opacity = 1.0,
labFormat = leaflet::labelFormat(transform = function(x) round(10^x)),title = ~Indicator[1])
```