Package 'ggmapinset'

Description

This package helps with making zoomed map insets. See geom_sf_inset().

Author(s)

Maintainer: Carl Suster [email protected] (ORCID)

Other contributors:

• Western Sydney Local Health District, NSW Health [copyright holder]

See Also

Useful links:

• https://github.com/cidm-ph/ggmapinset

• https://cidm-ph.github.io/ggmapinset/

• Report bugs at https://github.com/cidm-ph/ggmapinset/issues

Description

For plotting, use geom_sf_inset() instead. This helper is intended to be used when implementing custom geometries based on geom_sf_inset() so that they can provide parameters to control the inset.

Usage

build_sf_inset_layers(
  data,
  mapping,
  stat,
  position,
  show.legend,
  inherit.aes,
  params,
  inset,
  map_base = "normal",
  map_inset = "auto"
)

Arguments

Value

A ggplot layer, or a pair of layers.

Examples

my_custom_geom <- function(mapping = ggplot2::aes(),
                           data = NULL,
                           stat = "my_custom_stat",
                           position = "identity",
                           ...,
                           inset = NA,
                           map_base = "normal",
                           map_inset = "auto",
                           na.rm = TRUE,
                           inherit.aes = TRUE) {
  params <- rlang::list2(na.rm = na.rm, ...)
  build_sf_inset_layers(data = data, mapping = mapping,
                        stat = stat, position = position,
                        show.legend = show.legend,
                        inherit.aes = inherit.aes,
                        params = params,
                        inset = inset,
                        map_base = map_base,
                        map_inset = map_inset)
}

Description

The configuration returned by this function will normally be passed to the coordinate system via coord_sf_inset(). Insets can either be circular (if radius is specified) or rectangular (if hwidth and optionally hheight are specified).

Usage

configure_inset(
  centre,
  scale = NULL,
  translation = NULL,
  radius = NULL,
  hwidth = NULL,
  hheight = NULL,
  units = "km",
  crs_working = NULL
)

Arguments

Details

The default crs_working uses the equidistant cylindrical coordinate reference system with the latitude of true scale set to match the latitude of centre. This ensures that circular insets will appear circular in most cases since the projection is not distorted near the centre. The geometries are converted to this CRS for the inset transformation and constructing the inset frame, and are converted back to the CRS of centre at the end.

The default units are kilometres but can be changed with units instead of specifying the whole projection. The possible values for units are those understood by proj:

• "mm": millimetre

• "cm": centimetre

• "m": metre

• "ft": foot

• "us-ft": US survey foot

• "fath": fathom

• "kmi": nautical mile

• "us-ch": US survey chain

• "us-mi": US survey mile

• "km": kilometre

• "ind-ft": Indian foot (1937)

• "ind-yd": Indian yard (1937)

• "mi": Statute mile

• "yd": yard

• "ch": chain

• "link": link

• "dm": decimeter

• "in": inch

• "ind-ch": Indian chain

• "us-in": US survey inch

• "us-yd": US survey yard

Value

An inset configuration object of class inset_config.

Examples

library(sf)

# circular inset with a 2x enlargement
cfg <- configure_inset(
  centre = st_sfc(st_point(c(-82, 35)), crs = 4326),
  scale = 2,
  translation = c(70, -180),
  radius = 50,
  units = "mi")

Description

This allows a default inset configuration to be provided to avoid having to repeat it for each layer. Any layer that is inset-aware can use this as the default configuration if none is specifically provided to that layer. This coord also expands the axis limits to include the inset area.

Usage

coord_sf_inset(inset, ...)

Arguments

Value

A ggplot coordinate object to be added to a plot.

See Also

geom_sf_inset()

Examples

library(ggplot2)

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)

ggplot(nc) +
  geom_sf_inset(aes(fill = AREA)) +
  geom_inset_frame() +
  coord_sf_inset(inset = configure_inset(
    centre = sf::st_sfc(sf::st_point(c(-80, 35.5)), crs = 4326),
    scale = 1.5, translation = c(-50, -140), radius = 50, units = "mi"))

Description

The frame is computed from the inset configuration, so any data passed to this layer is ignored. The frame is an sf object consisting of three features: the source area, the target area (a scaled and translated version of the source area), and the connecting/burst lines.

Usage

geom_inset_frame(
  mapping = ggplot2::aes(),
  data = NULL,
  stat = "sf_inset",
  position = "identity",
  ...,
  inset = NA,
  na.rm = FALSE,
  source.aes = list(),
  target.aes = list(),
  lines.aes = list(),
  show.legend = NA,
  inherit.aes = FALSE
)

Arguments

Details

Burst lines for circular insets are bitangenets (tangent to both the source and target circles) or absent if the circles are nested. Burst lines for rectangular insets are the shortest line from each corner of the source rectangle to any corner of the target rectangle, after excluding any such lines that intersect either rectangle or each other. When the burst lines are absent due to geometrical constraints, there will still be a corresponding (empty) feature in the frame layer's data.

Value

A ggplot layer holding the inset frame.

Limitation

The frame cannot be drawn without another sf layer that contains data due to a limitation of the ggplot layout evaluation. Attempting to plot a frame by itself will result in the error: "Scale limits cannot be mapped onto spatial coordinates in coord_sf()".

Examples

library(ggplot2)

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)

ggplot(nc) +
  geom_sf_inset() +
  geom_inset_frame(
    source.aes = list(fill = "red", alpha = 0.2, linewidth = 0),
    target.aes = list(colour = "blue"),
    lines.aes = list(linetype = 2, linewidth = 2)
  ) +
  coord_sf_inset(inset = configure_inset(
    centre = sf::st_sfc(sf::st_point(c(-82, 35)), crs = 4326),
    scale = 4, translation = c(0, -260), radius = 50, units = "mi"))

make_demo <- function(...) {
  centroid <-
    sf::st_centroid(nc$geometry[[21]]) |>
    sf::st_sfc(crs = sf::st_crs(nc))

  ggplot(nc) +
    geom_sf(fill = "grey95", colour = "grey85") +
    # For a filled frame, we want to interleave it between the base layer
    # (above this line) and the target layer (below the following line).
    geom_inset_frame(target.aes = list(fill = "white")) +
    geom_sf_inset(map_base = "none") +
    coord_sf_inset(inset = configure_inset(centre = centroid, ...)) +
    theme_void()
}

# the lines connecting the frames vary depending on relative size and position:
make_demo(scale = 3, radius = 50, translation = c(-200, -200))
make_demo(scale = 3, radius = 50, translation = c(-100, -100))
make_demo(scale = 3, radius = 50, translation = c(0, 0))
make_demo(scale = 0.5, radius = 50, translation = c(0, 0))
make_demo(scale = 3, hwidth = 50, hheight = 40, translation = c(-300, 0))
make_demo(scale = 3, hwidth = 50, hheight = 40, translation = c(-250, -200))
make_demo(scale = 3, hwidth = 50, hheight = 40, translation = c(-150, -100))
make_demo(scale = 3, hwidth = 50, hheight = 40, translation = c(0, 0))
make_demo(scale = 0.5, hwidth = 50, hheight = 40, translation = c(0, 0))

Description

These geoms are wrappers around ggplot2::geom_sf() and its relatives that assist with creating map insets. In many cases all that is needed is to use coord_sf_inset() with configure_inset() to configure the location and transformation of the inset, and then replace the sf-related geoms with their ⁠_inset⁠ counterparts. Use geom_inset_frame() to add a frame around the inset that connects it to the main map.

Usage

geom_sf_inset(
  mapping = ggplot2::aes(),
  data = NULL,
  stat = "sf_inset",
  position = "identity",
  ...,
  inset = NA,
  map_base = "normal",
  map_inset = "auto",
  na.rm = TRUE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_sf_text_inset(
  mapping = aes(),
  data = NULL,
  stat = "sf_coordinates_inset",
  position = "identity",
  ...,
  where = "inset",
  parse = FALSE,
  check_overlap = FALSE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  fun.geometry = NULL
)

geom_sf_label_inset(
  mapping = aes(),
  data = NULL,
  stat = "sf_coordinates_inset",
  position = "identity",
  ...,
  where = "inset",
  parse = FALSE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  fun.geometry = NULL
)

stat_sf_inset(
  mapping = ggplot2::aes(),
  data = NULL,
  geom = "sf_inset",
  position = "identity",
  ...,
  inset = NA,
  na.rm = TRUE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

Details

Internally this works by creating two layers: one for the base map, and one for the inset. These can be separately controlled by the map_base and map_inset parameters. If inset is not specified, this geom will instead behave like ggplot2::geom_sf().

When an inset is configured, the default creates both base and inset layers using the same aesthetic mapping and params:

geom_sf_inset(...)

You can alternatively specify the two layers separately:

# draw the base map only (both versions are equivalent):
geom_sf(...)
geom_sf_inset(..., map_inset = "none")

# separately, draw the inset map only:
geom_sf_inset(..., map_base = "none")

stat_sf_inset() works the same ggplot2::stat_sf() except that it also expands the axis limits to account for the inset area.

Value

A ggplot layer similar to ggplot2::geom_sf() but transformed according to the inset configuration.

Examples

library(ggplot2)

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)

ggplot(nc) +
  geom_sf_inset(aes(fill = AREA)) +
  geom_inset_frame() +
  coord_sf_inset(inset = configure_inset(
    centre = sf::st_sfc(sf::st_point(c(-80, 35.5)), crs = sf::st_crs(nc)),
    scale = 1.5, translation = c(-50, -140), radius = 50, units = "mi"))

Description

This is a helper for implementing inset-aware ggplot layers. If the inset is missing (NA) then the default inset configuration is retrieved from the coord.

Usage

get_inset_config(inset, coord)

Arguments

Value

Inset configuration or NULL

Examples

# defining a new geom deriving from geom_sf()
GeomCustom <- ggplot2::ggproto("GeomCustom", ggplot2::GeomSf,
  draw_panel = function(self, data, panel_params, coord, inset = NA) {
    inset <- get_inset_config(inset, coord)

    # do something with the inset ...

    # note that this example doesn't pass on the remaining geom_sf params but
    # in real usage you would probably want to do that
    ggplot2::ggproto_parent(ggplot2::GeomSf, self)$draw_panel(data, panel_params, coord)
  },
)

Description

This dataset is derived from the NSW Arbovirus Surveillance and Mosquito Monitoring program. The program monitors mosquito-borne diseases in the state of New South Wales, Australia. A number of mosquito traps are managed by the program during the spring to autumn months when mosquitoes are active.

Usage

mozzies_nsw2301

Format

Data frame with the following fields:

location

Location of the mosquito trap

week_ending

Date of the end of the week of observation

species

Mosquito species counted, or "total" for the total count

count

Binned mosquito abundance

type

Category of the site

lat

Latitude of trap in WGS 84 coordinates

long

Longitude of trap in WGS 84 coordinates

Details

Each week traps are collected and the mosquito species are identified and counted. This is analysed alongside climate conditions, and arbovirus detections in the traps to inform public health management of human disease risk from arboviruses in NSW. This dataset includes the mosquito abundance tables for January 2023. Additional context and analysis can be found in the original report published by NSW Health.

The trap locations are classified as inland or coastal (since the species found will depend on the environmental conditions). A separate group of sites are labelled as being in the Sydney region (i.e. with the highest human population density).

The counts are binned with the following definition:

NA

No observation

low

< 50

medium

50 - 100

high

101 - 1,000

very high

1,001 - 10,000

extreme

> 10,000

Source

Surveillance and Risk Unit, Environmental Health Branch, Health Protection NSW, NSW Health. "NSW Arbovirus Surveillance and Mosquito Monitoring 2022-2023; Weekly Update: Week ending 25 February 2023 (Report Number 19)" https://www.health.nsw.gov.au/environment/pests/vector/Publications/nswasp-weekly-report-2023-02-25.pdf, accessed 15 January 2024.

The original dataset is published under the Creative Commons Attribution 4.0 licence © State of New South Wales NSW Ministry of Health 2023.

Description

Reduce spatial data to coordinates in the same way as stat_sf_coordinates(). The result can then be used by geom_sf() or geom_sf_inset() or any geom that needs x and y aesthetics.

Usage

stat_sf_coordinates_inset(
  mapping = ggplot2::aes(),
  data = NULL,
  geom = "point",
  position = "identity",
  ...,
  inset = NA,
  fun.geometry = NULL,
  where = "inset",
  na.rm = TRUE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

Value

A plot layer

Required aesthetics

geometry

The sf geometry column containing spatial features

Computed variables

x

X dimension of the simple feature

y

Y dimension of the simple feature

x_inset

X dimension of the simple feature after inset transformation

y_inset

Y dimension of the simple feature after inset transformation

inside_inset

logical indicating points inside the inset viewport

inset_scale

1 for points outside the inset, otherwise the configured inset scale parameter

Examples

library(ggplot2)

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)

ggplot(nc) +
  geom_sf_inset() +
  geom_inset_frame() +
  geom_sf_text(aes(x = after_stat(x_inset), y = after_stat(y_inset), label = NAME),
    stat = "sf_coordinates_inset") +
  coord_sf_inset(inset = configure_inset(
    centre = sf::st_sfc(sf::st_point(c(-80, 35.5)), crs = 4326),
    scale = 1.5, translation = c(-50, -140), radius = 50, units = "mi"))

Description

This helper operates on an sf object to scale and translate its geometry according to the inset specification.

Usage

transform_to_inset(x, inset)

Arguments

Value

A copy of x with the geometry replaced by the transformed version.

Examples

library(sf)

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)
cfg <- configure_inset(
  centre = st_sfc(st_point(c(-82, 35)), crs = 4326),
  scale = 2,
  translation = c(10, -60),
  radius = 50,
  units = "mi")

transform_to_inset(nc, cfg)