BoundsError when plotting linestrings with colour

[shriv]

Hi there,
I'm a beginner wanting to use GeoMakie for transport data science. Common use cases include colouring road segment linestrings with some value. However, I get a bounds error when trying the following reprex. The only approaches that work involve looping over the geoms for plotting or for creating a separate vector for x, y and colour. Is there something I'm doing wrong?

Triggered by update of:
  alpha, colormap, space, colorscale, clip_planes, projection, highclip, nan_color, viewport, arg1, f32c, model, colorrange, color, view, transform_func, linewidth or lowclip
Due to ERROR: BoundsError: attempt to access 3-element Vector{RGBA{Float32}} at index [4]

using CairoMakie, GeoMakie, ArchGDAL

wkt_strings = [
    "LINESTRING (174.70 -36.80, 174.73 -36.83, 174.76 -36.86, 174.80 -36.90)",
    "LINESTRING (174.80 -36.70, 174.83 -36.73, 174.86 -36.76, 174.90 -36.80)",
    "LINESTRING (174.60 -36.90, 174.63 -36.93, 174.66 -36.96, 174.70 -37.00)",
]
values = [1.0, 2.0, 3.0]

geoms = ArchGDAL.fromWKT.(wkt_strings)

fig = Figure()
ga = GeoAxis(fig[1, 1]; source = "+proj=longlat +datum=WGS84")
lines!(ga, geoms; color = values, colormap = :viridis)
fig

System

Julia 1.12.5
GeoMakie 0.7.16

[shriv]

Okay, so I think I understand the underlying issue now. lines is actually not a plotter for linestring geometries 🤦‍♀️ I had assumed that it would be because I can plot N linestrings without breaking into points.

Is this something that will be corrected? i.e. I can pass in N linestrings and N colours rather than needing to break the linestrings into M coordinates first.

[asinghvi17]

Ah, ok the issue here is that we have to internally insert NaN values between every linestring into a flattened vector of points. If you want to color the linestrings individually, I'd say you could either:

• Do that decomposition individually and assign colors per point
• Make a separate line plot per trace (admittedly not the best way to do it)
• Use series or some equivalent, though I'm not sure if that works

[shriv]

Thanks @asinghvi17 ! I've tried the first two and will stick with option 1. I'm not familiar with Series. I'll see if there are any examples online.

[shriv]

Are there any plans to make an equivalent lines plotter like poly? If not, I'm happy to close this issue..