8 changed files with 153 additions and 22 deletions
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#' Continuous fill scale for use with NWS raster radar data |
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#' |
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#' The dBZ values associated with the base reflectivity radar images/data represent |
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#' the strength of the energy returned to the radar from the precipitation. Values lower than 20 dBZ |
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#' are generally when there is actual light rain. The NWS tends to use a light gray alpha for values |
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#' below ~5 dBZ since there are particles in the air but they really aren't something that constitutes |
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#' precipitation.\cr |
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#' \cr |
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#' This `{ggplot2}` continuous fill scale is an adaptation of the `{viridis}` color palette scales |
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#' where the viridis scale mappings only start when dBZ values are around 5 dBZ. Values lower than that |
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#' receive light gray with a 5% alpha (see the `low_dbz` parameter). |
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#' |
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#' @param option,direction passed on to [viridis::viridis_pal()]; defaults to "`plasma`" and `-1`, respectively. |
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#' @param low_dbz color to be uses the dbZ values are lower than ~5 dBZ. Defaults to "`#00000010`" |
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#' @param name The name of the scale |
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#' @param na.value Missing values will be replaced with this value. Defaults to a fully transparent color. |
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#' @param limits scale limits; defaults to NWS dBZ limits [-30, 70] |
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#' @param breaks scale breaks; defaults to the NWS every 5 sequence from -30 to 70 |
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#' @param ... passed on to [ggplot2::scale_fill_gradientn()] |
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#' @return a `{ggplot2}` continuous fill scale |
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#' @export |
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#' @examples \dontrun{ |
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#' library(sf) |
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#' library(stars) |
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#' library(rradar) |
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#' library(rnaturalearth) |
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#' library(hrbrthemes) |
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#' library(tidyverse) |
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#' |
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#' us <- ne_states(country = "united states of america", returnclass = "sf") |
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#' |
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#' ne_radar <- latest_radar("northeast") |
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#' |
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#' ne_us <- st_crop(us, st_bbox(ne_radar)) |
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#' |
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#' ggplot() + |
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#' geom_sf(data = ne_us, size = 0.125, fill = '#fefefe') + |
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#' geom_stars(data = ne_radar) + |
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#' coord_sf(datum = NA) + |
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#' scale_fill_rradar() + |
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#' labs( |
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#' x = NULL, y = NULL, |
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#' title = "NWS Radar Mosaic — Northeast Sector", |
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#' subtitle = "1538 UTC 2019-12-07" |
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#' ) + |
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#' theme_ipsum_es(grid="") + |
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#' theme(legend.key.height = unit(5, "lines")) |
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#' } |
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scale_fill_rradar <- function(option = "plasma", direction = -1, name = "dBZ", na.value = "#00000000", |
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limits = c(-30, 70), breaks = seq(-30, 70, 5), low_dbz = "#00000010", ...) { |
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|
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dbz <- seq(-30, 70, 1) |
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dbzrs <- scales::rescale(dbz) |
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|
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ggplot2::scale_fill_gradientn( |
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colours = c(rep(low_dbz, 38), viridis::viridis_pal(option = option, direction = direction)(63)), |
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values = dbzrs, limits = limits, breaks = breaks, |
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na.value = na.value, name = name, ... |
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) |
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|
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} |
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% Generated by roxygen2: do not edit by hand |
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% Please edit documentation in R/scale-rradar.R |
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\name{scale_fill_rradar} |
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\alias{scale_fill_rradar} |
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\title{Continuous fill scale for use with NWS raster radar data} |
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\usage{ |
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scale_fill_rradar( |
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option = "plasma", |
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direction = -1, |
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name = "dBZ", |
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na.value = "#00000000", |
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limits = c(-30, 70), |
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breaks = seq(-30, 70, 5), |
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low_dbz = "#00000010", |
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... |
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) |
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} |
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\arguments{ |
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\item{option, direction}{passed on to \code{\link[viridis:viridis_pal]{viridis::viridis_pal()}}; defaults to "\code{plasma}" and \code{-1}, respectively.} |
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|
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\item{name}{The name of the scale} |
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|
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\item{na.value}{Missing values will be replaced with this value. Defaults to a fully transparent color.} |
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|
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\item{limits}{scale limits; defaults to NWS dBZ limits \link{-30, 70}} |
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|
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\item{breaks}{scale breaks; defaults to the NWS every 5 sequence from -30 to 70} |
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|
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\item{low_dbz}{color to be uses the dbZ values are lower than ~5 dBZ. Defaults to "\verb{#00000010}"} |
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|
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\item{...}{passed on to \code{\link[ggplot2:scale_fill_gradientn]{ggplot2::scale_fill_gradientn()}}} |
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} |
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\value{ |
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a \code{{ggplot2}} continuous fill scale |
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} |
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\description{ |
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The dBZ values associated with the base reflectivity radar images/data represent |
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the strength of the energy returned to the radar from the precipitation. Values lower than 20 dBZ |
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are generally when there is actual light rain. The NWS tends to use a light gray alpha for values |
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below ~5 dBZ since there are particles in the air but they really aren't something that constitutes |
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precipitation.\cr |
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\cr |
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This \code{{ggplot2}} continuous fill scale is an adaptation of the \code{{viridis}} color palette scales |
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where the viridis scale mappings only start when dBZ values are around 5 dBZ. Values lower than that |
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receive light gray with a 5\% alpha (see the \code{low_dbz} parameter). |
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} |
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