googleway (version 2.0.0)

add_heatmap: Add heatmap

Description

Adds a heatmap to a google map

Usage

add_heatmap(map, data = get_map_data(map), lat = NULL, lon = NULL,
  weight = NULL, option_gradient = NULL, option_dissipating = FALSE,
  option_radius = 0.01, option_opacity = 0.6, layer_id = NULL)

Arguments

map

a googleway map object created from google_map()

data

data frame containing at least two columns, one specifying the latitude coordinates, and the other specifying the longitude. If Null, the data passed into google_map() will be used.

lat

string specifying the column of data containing the 'latitude' coordinates. If left NULL, a best-guess will be made

lon

string specifying the column of data containing the 'longitude' coordinates. If left NULL, a best-guess will be made

weight

string specifying the column of data containing the 'weight' associated with each point. If NULL, each point will get a weight of 1.

option_gradient

vector of colours to use as the gradient colours. see Details

option_dissipating

logical Specifies whether heatmaps dissipate on zoom. When dissipating is FALSE the radius of influence increases with zoom level to ensure that the color intensity is preserved at any given geographic location. Defaults to FALSE

option_radius

numeric. The radius of influence for each data point, in pixels.

option_opacity

The opacity of the heatmap, expressed as a number between 0 and 1. Defaults to 0.6.

layer_id

single value specifying an id for the layer.

Details

option_gradient colours can be two of the R colour specifications; either a colour name (as listed by colors(), or a hexadecimal string of the form "#rrggbb"). The first colour in the vector will be used as the colour that fades to transparent, while the last colour in the vector will be use in the centre of the 'heat'.

Examples

# NOT RUN {
map_key <- 'your_api_key'

set.seed(20170417)
df <- tram_route
df$weight <- sample(1:10, size = nrow(df), replace = T)

google_map(key = map_key, data = df) %>%
 add_heatmap(lat = "shape_pt_lat", lon = "shape_pt_lon", weight = "weight",
              option_radius = 0.001)

## specifying different colour gradient
option_gradient <- c('orange', 'blue', 'mediumpurple4', 'snow4', 'thistle1')

google_map(key = map_key, data = df) %>%
 add_heatmap(lat = "shape_pt_lat", lon = "shape_pt_lon", weight = "weight",
              option_radius = 0.001, option_gradient = option_gradient)

 
# }