Quadrilateral Mesh

from std.math import exp, sin

from dataviz import pcolormesh
from dataviz.core.colormaps import magma
from dataviz import save
from dataviz import Theme

def main() raises:
    # Weather balloons are farther apart downrange and report at
    # uneven altitude bands, so each cell keeps its measured extent.
    var x_edges: List[Float64] = [
        0, 3, 7, 12, 18, 25, 33, 42, 52, 63, 75, 88, 102,
    ]
    var y_edges: List[Float64] = [
        0.0, 0.4, 0.9, 1.5, 2.3, 3.3, 4.6, 6.2, 8.0,
    ]

    var z = List[List[Float64]]()
    for r in range(len(y_edges) - 1):
        var row = List[Float64]()
        var altitude = (y_edges[r] + y_edges[r + 1]) / 2.0
        for c in range(len(x_edges) - 1):
            var distance = (x_edges[c] + x_edges[c + 1]) / 2.0
            var plume_x = (distance - 55.0) / 18.0
            var plume_y = (altitude - 2.2) / 0.9
            var temperature = 19.0 - 6.2 * altitude
            temperature += 2.0 * sin(distance / 17.0)
            temperature += 8.0 * exp(
                -(plume_x * plume_x + plume_y * plume_y)
            )
            row.append(temperature)
        z.append(row^)

    var chart = pcolormesh(
        x_edges,
        y_edges,
        z,
        theme=Theme(color_ramp=magma()),
        title="Illustrative Atmospheric Temperature Cross-Section (°C)",
        x_title="Distance downrange (km)",
        y_title="Altitude (km)",
    )
    save(chart, "docs/src/examples/out_pcolormesh.svg")