Course 9 - Developing Data Products - Week 2 - Notes

R Markdown Presentations

A new slide is a level 2 heading “##”.

To do a slide without a title, start with ’***’.

When running R code, you can set comment = "" to set the comment character or remove it completely:

head(mtcars)

##                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
## Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
## Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
## Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
## Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
## Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
## Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

head(mtcars)

                   mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

Leaflet

Allows for the creation of interactive maps.

library(leaflet)
leaflet() %>% 
    addTiles()

The mapping data is from OpenStreeMap.

We can add a marker:

leaflet() %>% 
    addTiles() %>% 
    addMarkers(lat = -37.7298, lng = 144.9553, popup = 'Coburg Velodrome')

You can add HTML into the popups, e.g. anchors/links.

To add many markers, you can create a data frame:

tibble(
    lat = -c(36, 37, 38),
    lng = c(143, 144, 145)
) %>% 
    leaflet() %>% 
    addTiles() %>% 
    addMarkers()

Custom Markers

ccc_icon <- makeIcon(
    iconUrl = 'https://scontent.fmel7-1.fna.fbcdn.net/v/t31.0-1/cp0/c7.0.56.56a/p56x56/12045418_1173078239386251_5340026945367359072_o.jpg?_nc_cat=106&_nc_sid=dbb9e7&_nc_ohc=CVP7qbMvVsoAX_B5sru&_nc_ht=scontent.fmel7-1.fna&oh=e8ba7d82868ac3198b6a2771a32ecc39&oe=5EA97D59'
)

leaflet() %>% 
    addTiles() %>% 
    addMarkers(lat = -37.7298, lng = 144.9553, popup = 'Coburg Velodrome', icon = ccc_icon)

Mapping Clusters

tibble(
    lat = runif(500, min = -37.8, max = -37.7),
    lng = runif(500, min = 144.8, max = 145)
) %>% 
    leaflet() %>% 
    addTiles() %>% 
    addMarkers(clusterOptions = markerClusterOptions())

You can add circle markers:

tibble(
    lat = runif(500, min = -37.8, max = -37.7),
    lng = runif(500, min = 144.8, max = 145)
) %>% 
    leaflet() %>% 
    addTiles() %>% 
    addCircleMarkers()

Can use a variable in the data frame to determine the radius.

Legend

Can add a legend with addLegend().