graceful handling for missing in add_circle_layer

[ews-grmunjal]

if one of the values in the column is NA... no circles are rendered

good behaviour could be to have a na.rm type argument, if TRUE, dont render NA circles, if FALSE, NAs can be rendered as a separate category

[ews-grmunjal]

reproducible example:

library(mapgl)
library(sf)
library(dplyr)

nc <- st_read(system.file('shape/nc.shp', package = 'sf'))

WORKS

numcolors <- 6
nc <- nc %>% mutate(zz = sample(letters[1:numcolors], nrow(.), replace = T))
magma_pal <- viridisLite::magma(numcolors)
magma_substr_pal <- substr(magma_pal, 1, 7)

mapboxgl() %>%
fit_bounds(nc, animate = F) %>%
add_circle_layer(
id = 'GC Zones',
source = nc,
circle_color = match_expr(
column = 'zz',
values = unique(nc$zz),
stops = magma_substr_pal
)
) %>%
add_legend(
'GC Zones',
values = unique(nc$zz),
colors = magma_substr_pal,
type = 'categorical'
)

DOES NOT WORK

nc$zz[1] <- NA
numcolors <- 7
magma_pal <- viridisLite::magma(numcolors)
magma_substr_pal <- substr(magma_pal, 1, 7)

mapboxgl() %>%
fit_bounds(nc, animate = F) %>%
add_circle_layer(
id = 'GC Zones',
source = nc,
circle_color = match_expr(
column = 'zz',
values = unique(nc$zz),
stops = magma_substr_pal
)
) %>%
add_legend(
'GC Zones',
values = unique(nc$zz),
colors = magma_substr_pal,
type = 'categorical'
)