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Multi-panel map layouts

geo-panels.Rd

Figures with more than one map, ready for a paper or report:

  • geo_panels() arranges maps (from geo_map(), geo_automap() or any ggplot) in a grid with panel tags such as (a), (b). Legends that are the same in every panel are collected into one.

  • geo_facet_map() draws small multiples: one map per group (year, season, species) with one classification shared by all panels, so a colour means the same value everywhere, one legend, and the scale bar and north arrow in the first panel only.

  • geo_inset() places a small map (for example a locator of the study area) inside a corner of a larger one.

All three need the patchwork package; the result is a patchwork object that prints as one figure and saves with geo_save().

Usage

geo_panels(
  ...,
  ncol = NULL,
  nrow = NULL,
  tags = c("a", "A", "1", "i", "I", "none"),
  tag_prefix = "(",
  tag_suffix = ")",
  guides = c("collect", "keep"),
  legend_position = c("right", "bottom"),
  title = NULL,
  subtitle = NULL,
  caption = NULL,
  widths = NULL,
  heights = NULL
)

geo_facet_map(
  data,
  value,
  by = NULL,
  ncol = NULL,
  n = 5,
  style = c("quantile", "jenks", "equal", "pretty", "sd"),
  palette = "YlOrRd",
  legend_title = NULL,
  title = NULL,
  scale_bar = "pill",
  north_arrow = "needle"
)

geo_inset(main, inset, location = "auto", size = 0.3)

Arguments

...

Maps: tmr_map objects from geo_map() or ggplots.

ncol, nrow

Grid size; by default as square as possible.

tags

Panel tags: "a" (default), "A", "1", "i", "I", or "none".

tag_prefix, tag_suffix

Text around each tag; the default gives (a), (b), ...

guides

"collect" merges legends that are the same in several panels into one; "keep" leaves a legend beside each panel.

legend_position

Where collected legends go: "right" or "bottom". Legends kept per panel stay at the right of their panel.

title, subtitle, caption

Figure title, subtitle and caption.

widths, heights

Relative widths of the columns and heights of the rows.

data

An sf table.

value

<data-masking> Numeric column to map.

by

<data-masking> Column that splits the data into panels. Alternatively give several value columns in value with c(), one panel per column.

n, style

Shared classification, passed to geo_classify().

palette

Colour ramp: a name from grDevices::hcl.pals() or a vector of colours.

legend_title

Legend title; defaults to the column name.

scale_bar, north_arrow

Styles of the scale bar and north arrow, drawn in the first panel; FALSE to leave them out.

main, inset

The large map and the small one.

location

Where the inset goes: "auto" (default) picks a corner free of the scale bar, north arrow and any legend inside the map, and of those the one hiding the least of the mapped features; "tr", "tl", "br" or "bl" names a corner; or two numbers give the inset's lower-left corner anywhere on the map, as fractions of the map panel (for example c(0.05, 0.6)).

size

Width and height of the inset as a fraction of the main map.

Value

A patchwork object (geo_panels(), geo_inset()) or a ggplot (geo_facet_map()).

See also

geo_map(), geo_automap(), geo_save().

Examples

nc <- sf::st_read(system.file("shape/nc.shp", package = "sf"), quiet = TRUE)
nc$`1974-78` <- 1000 * nc$SID74 / nc$BIR74
nc$`1979-84` <- 1000 * nc$SID79 / nc$BIR79

# Two periods, one classification, one legend
geo_facet_map(nc, c(`1974-78`, `1979-84`), n = 5,
  legend_title = "SIDS per 1000 births")


# Any maps side by side, tagged (a) and (b)
a <- geo_automap(nc, `1974-78`)
b <- geo_automap(nc, BIR74, legend_title = "Births 1974-78")
geo_panels(a, b, ncol = 1, title = "North Carolina")