Max value seems to disappear when low end changed. Difficult to replicate.

[stevenpandrews]

Looks really neat! I'll definitely be using this feature.

On my first test to see what it does, I ran into a curious issue where the max value disappeared when I changed the minimum slider:

The only way to get back the max value is by clicking the "Reset Filter" button. I can't just drag it back.

I couldn't replicate it by manually writing in the values as seen in this script and I couldn't get it to happen on any other dataset 🤷 .

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

# Filters out max value when filtering out minimum.
# Max value does not return when filter manually returned.
# Must "reset filter" to it come back.
ex <- sf::read_sf("./example_filter.json")
maplibre_view(ex, column = "sqrt", interactive_legend = TRUE)

# Copy and pasting the values appears to work as expected:
ex2 <- sf::read_sf("./example_filter.json") |> 
  mutate(vals = c(142.324201930084, 141.097151409605, 131.363452690700, 130.516571591330))

maplibre_view(ex2, column = "vals", interactive_legend = TRUE, palette = viridis::turbo)

example_filter.json (github wouldn't let me upload a geojson but the script produced the same results either way)

Originally posted by @stevenpandrews in #138

[walkerke]

Thanks! Been working on this, and learned something new!

This is what Claude explained to me:

Yes, it's a floating-point precision issue that happens during JSON serialization between R and JavaScript.

  Here's what happens:

  1. R data value: 142.32420193008412 (full precision)
  2. R computes breaks: seq(min, max, length.out=5) → last element should equal max
  3. JSON serialization: The number gets truncated slightly to 142.3242019300841
  4. JS filter: ["<=", column, 142.3242019300841]
  5. GeoJSON property: Still has 142.32420193008412

  Result: 142.32420193008412 <= 142.3242019300841 is FALSE (by ~2.8e-14), so the max feature gets excluded.

It's fixed now. As a bonus, try out the new draggable = TRUE parameter for legends as well!

[stevenpandrews]

Fun! you can drag your legend like a ph test strip: