Update polylines

Updates specific attributes of polylines. Designed to be used in a shiny application.

update_polylines(map, data, id, stroke_colour = NULL,
  stroke_weight = NULL, stroke_opacity = NULL, info_window = NULL,
  layer_id = NULL, palette = NULL, legend = F,
  legend_options = NULL)

Arguments

map	a googleway map object created from google_map()
data	data frame containing the data to use in the layer. If Null, the data passed into google_map() will be used.
id	string representing the column of data containing the id values for the shapes. The id values must be present in the original data supplied to in order for the shape to be udpated.
stroke_colour	either a string specifying the column of data containing the stroke colour of each shape, or a valid hexadecimal numeric HTML style to be applied to all the shapes
stroke_weight	either a string specifying the column of data containing the stroke weight of each shape, or a number indicating the width of pixels in the line to be applied to all the shapes
stroke_opacity	either a string specifying the column of data containing the stroke opacity of each shape, or a value between 0 and 1 that will be applied to all the shapes
info_window	string specifying the column of data to display in an info window when a shape is clicked.
layer_id	single value specifying an id for the layer. Use this value to distinguish between shape layers for when using any update_ function, and for separating legends.
palette	a function, or list of functions, that generates hex colours given a single number as an input. See details.
legend	either a logical indiciating if the legend(s) should be displayed, or a named list indicating which colour attributes should be included in the legend.
legend_options	A list of options for controlling the legend.

Note

Any polylines (as specified by the id argument) that do not exist in the data passed into add_polylines() will not be added to the map. This function will only update the polylines that currently exist on the map when the function is called.

Examples

# NOT RUN {
map_key <- 'your_api_key'

## coordinate columns
## plot polylines using default attributes
df <- tram_route
df$id <- c(rep(1, 27), rep(2, 28))

df$colour <- c(rep("#00FFFF", 27), rep("#FF00FF", 28))

google_map(key = map_key) %>%
  add_polylines(data = df, lat = 'shape_pt_lat', lon = 'shape_pt_lon',
                stroke_colour = "colour", id = 'id')

## specify width and colour attributes to update
df_update <- data.frame(id = c(1,2),
                        width = c(3,10),
                        colour = c("#00FF00", "#DCAB00"))

google_map(key = map_key) %>%
  add_polylines(data = df, lat = 'shape_pt_lat', lon = 'shape_pt_lon',
                stroke_colour = "colour", id = 'id') %>%
  update_polylines(data = df_update, id = 'id', stroke_weight = "width",
                   stroke_colour = 'colour')


## encoded polylines
pl <- sapply(unique(df$id), function(x){
  encode_pl(lat = df[ df$id == x , 'shape_pt_lat'], lon = df[ df$id == x, 'shape_pt_lon'])
})

df <- data.frame(id = c(1, 2), polyline = pl)

df_update <- data.frame(id = c(1,2),
                        width = c(3,10),
                        var = c("a","b"))

google_map(key = map_key) %>%
  add_polylines(data = df, polyline = 'polyline')

google_map(key = map_key) %>%
  add_polylines(data = df, polyline = 'polyline') %>%
  update_polylines(data = df_update, id = 'id', stroke_weight = "width",
                   stroke_colour = 'var')

# }