shiny_dashboard_sol.Rmd

---
title: "Untitled"
output:
  flexdashboard::flex_dashboard:
    orientation: columns
    vertical_layout: fill
runtime: shiny
---

```{r setup, include=FALSE}
# General environment / data preparation
library(flexdashboard)
library(shiny)
library(leaflet)
library(raster)
Hypoxia <- raster('data/Hypoxia.tif')
Acidification <- raster('data/Acidification.tif')
FisheriesDD <- raster('data/FisheriesDD.tif')

# Transform FisheriesDD
FisheriesDD <- FisheriesDD / maxValue(FisheriesDD)
names(FisheriesDD) <- 'FisheriesDD'

# Change projections
prj <- '+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext  +no_defs'
Hypoxia <- projectRaster(Hypoxia, crs = CRS(prj))
Acidification <- projectRaster(Acidification, crs = CRS(prj))
FisheriesDD <- projectRaster(FisheriesDD, crs = CRS(prj))

# Raster stack
rstack <- stack(Hypoxia, Acidification, FisheriesDD)
```

## Column {.sidebar}

This sidebar offers the user to select which raster to visualize and combine. Under the hood, the server functions -- that is, the back end -- runs a function to sum the values of the selected rasters.

```{r select, echo = FALSE}
radioButtons(inputId = 'raster',
             label = 'Rasters to select',
             choices = c("Hypoxia" = "Hypoxia",
                         "Fisheries" = "FisheriesDD",
                         "Acidification" = "Acidification"))
```

<br/>

We add another control widget to select which rasters on which to apply a function.

```{r, select2}
# Checkbox input
checkboxGroupInput(
  inputId = 'raster2',
  label = "Rasters to combine",
  choices = c("Hypoxia" = "Hypoxia",
              "Fisheries" = "FisheriesDD",
              "Acidification" = "Acidification"),
  selected = 'Hypoxia'
)
```


Column {data-width=650}
-----------------------------------------------------------------------

### Chart A

```{r}
leafletOutput(outputId = "map", height = 800)

output$map <- renderLeaflet({
 leaflet() %>%
 addProviderTiles("CartoDB.Positron") %>%
 addRasterImage(rstack[[input$raster]], project = FALSE)
})

```

Column {data-width=350}
-----------------------------------------------------------------------

### Chart B

```{r}
leafletOutput(outputId = "map2")

# Leaflet base map
output$map2 <- renderLeaflet({
  leaflet() %>%
  addProviderTiles(provider = providers$CartoDB.Positron) %>%
  setView(lng = -65, lat = 48.50, zoom  = 5)
})

# Function to calculate raster
rasterFunction <- reactive({
  if (length(input$raster2) > 1) {
    sum(rstack[[input$raster2]], na.rm = T) %>%
    calc(function(x) ifelse(x == 0, NA, x))
  } else {
    rstack[[input$raster2]]
  }
})

# Update map
observe({
  # Clear maps if no raster is selected
  if (length(input$raster2) == 0) {
    leafletProxy(mapId = "map2") %>%
    clearImages()
  } else if (length(input$raster2) > 0) {
    leafletProxy(mapId = "map2") %>%
    clearImages() %>%
    addRasterImage(x = rasterFunction(), project = FALSE)
  }
})
```

### Chart C

```{r}

```