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The interactive map of a group's segments under two rules

Source: R/compare_map.R
knw_compare_mapgl.Rd

The page knw_compare_map() saves when given html, as a mapgl widget to print in an R Markdown page or save: accessible segments coloured by rule (kept by both, lost, gained, neither) and, on a second layer the switch at the top right turns on, by grade class, each with its legend at the top left; lakes and rivers styled through gq's registry where it loads. Clicking a segment opens a popup with the fields it carries among the stream order, grade, mean annual flow (mad), channel width, gradient, the walk distance to the rule's river (dist_m), the waterbody it lies in (water, water_ha), and each rule's verdict, saying where the hand-entered reaches or the step that keeps rearing only where it connects to spawning changed it (pre_default, pre_tuned, the verdict from the habitat test alone).

Usage

knw_compare_mapgl(
  segments,
  water = NULL,
  title = "",
  background = c("voyager", "openfreemap", "esri_topo"),
  digits = 5L
)

Arguments

segments

an sf in EPSG:3005 with accessible, stream_order, grade_class and the two logical rule columns flag_default and flag_tuned.

water

an sf of lake and river polygons for the group, or NULL.

title

character(1) the rules legend's title.

background

"voyager" (Carto Voyager), "openfreemap" (OpenFreeMap Liberty) or "esri_topo" (Esri's World Topographic Map raster tiles, keyless; Esri allows free noncommercial use with attribution, which the map shows).

digits

integer(1) decimal places kept in the coordinates.

Value

A maplibregl htmlwidget, or NULL with a message when no segment is accessible.

Details

Coordinates are rounded to digits decimal degrees after the transform to EPSG:4326 (5 is about 1 m), and only the drawn and popup fields are kept, which sets the page's size.

Examples

if (requireNamespace("mapgl", quietly = TRUE)) {
  seg <- sf::st_sf(
    accessible = TRUE, stream_order = 1:3, grade_class = c("0-0.2", "0.8-1", NA),
    flag_default = c(TRUE, TRUE, FALSE), flag_tuned = c(TRUE, FALSE, TRUE), mad = c(0.4, 2.1, 0.1),
    geometry = sf::st_sfc(lapply(0:2, function(i) {
      sf::st_linestring(rbind(c(1e6 + i * 500, 1e6), c(1e6 + (i + 1) * 500, 1e6 + 300)))
    }), crs = 3005)
  )
  m <- knw_compare_mapgl(seg, title = "Habitat by rule")
  class(m)
}
#> [1] "maplibregl" "htmlwidget"