add_polygons: Add polygon

In googleway: Accesses Google Maps APIs to Retrieve Data and Plot Maps

Add polygon

Description

Add a polygon to a google map.

Usage

add_polygons(
  map,
  data = get_map_data(map),
  polyline = NULL,
  lat = NULL,
  lon = NULL,
  id = NULL,
  pathId = NULL,
  stroke_colour = NULL,
  stroke_weight = NULL,
  stroke_opacity = NULL,
  fill_colour = NULL,
  fill_opacity = NULL,
  info_window = NULL,
  mouse_over = NULL,
  mouse_over_group = NULL,
  draggable = NULL,
  editable = NULL,
  update_map_view = TRUE,
  layer_id = NULL,
  z_index = NULL,
  digits = 4,
  palette = NULL,
  legend = F,
  legend_options = NULL,
  load_interval = 0,
  focus_layer = FALSE
)

Arguments

map	a googleway map object created from google_map()
data	data frame containing at least a polyline column, or a lat and a lon column. If Null, the data passed into google_map() will be used.
polyline	string specifying the column of data containing the encoded polyline
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
id	string specifying the column containing an identifier for a shape
pathId	string specifying the column containing an identifer for each path that forms the complete polygon. Not required when using polyline, as each polyline is itself a path.
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
fill_colour	either a string specifying the column of data containing the fill colour of each shape, or a valid hexadecimal numeric HTML style to be applied to all the shapes
fill_opacity	either a string specifying the column of data containing the fill 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.
mouse_over	string specifying the column of data to display when the mouse rolls over the shape
mouse_over_group	string specifying the column of data specifying which groups of shapes to highlight on mouseover
draggable	string specifying the column of data defining if the polygon is 'draggable'. The column of data should be logical (either TRUE or FALSE)
editable	string specifying the column of data defining if the polygon is 'editable' (either TRUE or FALSE)
update_map_view	logical specifying if the map should re-centre according to the shapes
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.
z_index	single value specifying where the circles appear in the layering of the map objects. Layers with a higher z_index appear on top of those with a lower z_index. See details.
digits	integer. Use this parameter to specify how many digits (decimal places) should be used for the latitude / longitude coordinates.
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.
load_interval	time in miliseconds to wait between plotting each shape
focus_layer	logical indicating if the map should re-centre according to this layer

Details

z_index values define the order in which objects appear on the map. Those with a higher value appear on top of those with a lower value. The default order of objects is (1 being underneath all other objects)

• 1. Polygon

• 2. Rectangle

• 3. Polyline

• 4. Circle

Markers are always the top layer

palette

The palette is used to specify the colours that will map to variables. You can specify a single function to map to all variables, or a named list that specifies a separate function to map to each variable. The elements must be named either fill_colour or stroke_colour, and their values are the colour generating functions. The default is viridisLite::viridis

The legend_options can be used to control the appearance of the legend. This should be a named list, where the names are one of

• position - one of c("TOP_LEFT", "TOP_CENTER", "TOP_RIGHT", "RIGHT_TOP", "RIGHT_CENTER", "RIGHT_BOTTOM", "BOTTOM_RIGHT", "BOTTOM_CENTER", "BOTTOM_LEFT", "LEFT_BOTTOM", "LEFT_CENTER", "LEFT_TOP")

• css - a string of valid css for controlling the appearance of the legend

• title - a string to use for the title of the legend

if legend_options are NULL, the default values will apply

If you are displaying two legends, one for stroke_colour and one for fill_colour, you can specify different options for the different colour attributes. See examples for add_circles.

Note

A polygon represents an area enclosed by a closed path. Polygon objects are similar to polylines in that they consist of a series of coordinates in an ordered sequence. Polygon objects can describe complex shapes, including

• Multiple non-contiguous areas defined by a single polygon

• Areas with holes in them

• Intersections of one or more areas

To define a complex shape, you use a polygon with multiple paths.

To create a hole in a polygon, you need to create two paths, one inside the other. To create the hole, the coordinates of the inner path must be wound in the opposite order to those defining the outer path. For example, if the coordinates of the outer path are in clockwise order, then the inner path must be anti-clockwise.

You can represent a polygon in one of three ways

• as a series of coordinates defining a path (or paths) with both an id and pathId argument that make up the polygon

• as an encoded polyline using an id column to specify multiple polylines for a polygon

• as a list column in a data.frame, where each row of the data.frame contains the polylines that comprise the polygon

See Examples

See Also

encode_pl

Examples

## Not run: 

map_key <- 'your_api_key'

## polygon with a hole - Bermuda triangle
## using one row per polygon, and a list-column of encoded polylines
pl_outer <- encode_pl(lat = c(25.774, 18.466,32.321),
      lon = c(-80.190, -66.118, -64.757))

pl_inner <- encode_pl(lat = c(28.745, 29.570, 27.339),
       lon = c(-70.579, -67.514, -66.668))

df <- data.frame(id = c(1, 1),
       polyline = c(pl_outer, pl_inner),
       stringsAsFactors = FALSE)

df <- aggregate(polyline ~ id, data = df, list)

google_map(key = map_key, height = 800) %>%
    add_polygons(data = df, polyline = "polyline")

## the same polygon, but using an 'id' to specify the polygon
df <- data.frame(id = c(1,1),
       polyline = c(pl_outer, pl_inner),
       stringsAsFactors = FALSE)

google_map(key = map_key, height = 800) %>%
    add_polygons(data = df, polyline = "polyline", id = "id")

## the same polygon, specified using coordinates, and with a second independent
## polygon
df <- data.frame(myId = c(1,1,1,1,1,1,2,2,2),
      lineId = c(1,1,1,2,2,2,1,1,1),
      lat = c(26.774, 18.466, 32.321, 28.745, 29.570, 27.339, 22, 23, 22),
      lon = c(-80.190, -66.118, -64.757, -70.579, -67.514, -66.668, -50, -49, -51),
      colour = c(rep("#00FF0F", 6), rep("#FF00FF", 3)),
      stringsAsFactors = FALSE)

google_map(key = map_key) %>%
  add_polygons(data = df, lat = 'lat', lon = 'lon', id = 'myId', pathId = 'lineId',
               fill_colour = 'colour')




## End(Not run)

googleway documentation built on Aug. 22, 2023, 9:13 a.m.