geojsonio (version 0.7.0)

geojson_style: Style a data.frame or list prior to converting to geojson

Description

This helps you add styling following the Simplestyle Spec. See Details

Usage

geojson_style(input, var = NULL, var_col = NULL, var_sym = NULL,
  var_size = NULL, var_stroke = NULL, var_stroke_width = NULL,
  var_stroke_opacity = NULL, var_fill = NULL,
  var_fill_opacity = NULL, color = NULL, symbol = NULL,
  size = NULL, stroke = NULL, stroke_width = NULL,
  stroke_opacity = NULL, fill = NULL, fill_opacity = NULL)

Arguments

input

A data.frame or a list

var

(character) A single variable to map colors, symbols, and/or sizes to.

var_col

(character) A single variable to map colors to.

var_sym

(character) A single variable to map symbols to.

var_size

(character) A single variable to map size to.

var_stroke

(character) A single variable to map stroke to.

var_stroke_width

(character) A single variable to map stroke width to.

var_stroke_opacity

(character) A single variable to map stroke opacity to.

var_fill

(character) A single variable to map fill to.

var_fill_opacity

(character) A single variable to map fill opacity to.

color

(character) Valid RGB hex color. Assigned to the variable marker-color

symbol

(character) An icon ID from the Maki project http://www.mapbox.com/maki/ or a single alphanumeric character (a-z or 0-9). Assigned to the variable marker-symbol

size

(character) One of 'small', 'medium', or 'large'. Assigned to the variable marker-size

stroke

(character) Color of a polygon edge or line (RGB). Assigned to the variable stroke

stroke_width

(numeric) Width of a polygon edge or line (number > 0). Assigned to the variable stroke-width

stroke_opacity

(numeric) Opacity of a polygon edge or line (0.0 - 1.0). Assigned to the variable stroke-opacity

fill

(character) The color of the interior of a polygon (GRB). Assigned to the variable fill

fill_opacity

(character) The opacity of the interior of a polygon (0.0-1.0). Assigned to the variable fill-opacity

Details

The parameters color, symbol, size, stroke, stroke_width, stroke_opacity, fill, and fill_opacity expect a vector of size 1 (recycled), or exact length of vector being applied to in your input data.

This function helps add styling data to a list or data.frame following the Simplestyle Spec (https://github.com/mapbox/simplestyle-spec/tree/master/1.1.0), used by MapBox and GitHub Gists (that renders geoJSON/topoJSON as interactive maps).

There are a few other style variables, but deal with polygons

GitHub has a nice help article on geoJSON files https://help.github.com/articles/mapping-geojson-files-on-github/

Please do get in touch if you think anything should change in this function.

Examples

# NOT RUN {
## from data.frames - point data
library("RColorBrewer")
smalluscities <-
   subset(us_cities, country.etc == 'OR' | country.etc == 'NY' | country.etc == 'CA')

### Just color
geojson_style(smalluscities, var = 'country.etc',
   color=brewer.pal(length(unique(smalluscities$country.etc)), "Blues"))
### Just size
geojson_style(smalluscities, var = 'country.etc', size=c('small','medium','large'))
### Color and size
geojson_style(smalluscities, var = 'country.etc',
   color=brewer.pal(length(unique(smalluscities$country.etc)), "Blues"),
   size=c('small','medium','large'))

## from lists - point data
mylist <- list(list(latitude=30, longitude=120, state="US"),
               list(latitude=32, longitude=130, state="OR"),
               list(latitude=38, longitude=125, state="NY"),
               list(latitude=40, longitude=128, state="VT"))
# just color
geojson_style(mylist, var = 'state',
   color=brewer.pal(length(unique(sapply(mylist, '[[', 'state'))), "Blues"))
# color and size
geojson_style(mylist, var = 'state',
   color=brewer.pal(length(unique(sapply(mylist, '[[', 'state'))), "Blues"),
   size=c('small','medium','large','large'))
# color, size, and symbol
geojson_style(mylist, var = 'state',
   color=brewer.pal(length(unique(sapply(mylist, '[[', 'state'))), "Blues"),
   size=c('small','medium','large','large'),
   symbol="zoo")
# stroke, fill
geojson_style(mylist, var = 'state',
   stroke=brewer.pal(length(unique(sapply(mylist, '[[', 'state'))), "Blues"),
   fill=brewer.pal(length(unique(sapply(mylist, '[[', 'state'))), "Greens"))

# from data.frame - polygon data
smallstates <- states[states$group %in% 1:3, ]
head(smallstates)
geojson_style(smallstates, var = 'group',
   stroke = brewer.pal(length(unique(smallstates$group)), "Blues"),
   stroke_width = c(1, 2, 3),
   fill = brewer.pal(length(unique(smallstates$group)), "Greens"))
# }