feat: Detect mountain pass crossings, name climbs after passes, render ride charts

- osmpass: extract mountain_pass=yes nodes from an OSM PBF, enrich centcols passes with OSM coordinates, resumable -fetch-osm download
- mountain_pass: DetectCrossings for a ride, MatchClimb to name a climb after the pass it tops
- ride: expose Points(), add Climb.Top() and Climb.Name
- chart: -chart renders elevation profile with climb bands and pass markers
- commands: -fetch-osm, -extract-osm, -import-cached, -enrich

1 files changed, 81 insertions, 0 deletions

diff --git a/chart.go b/chart.go
new file mode 100644
index 0000000..063b495
--- /dev/null
+++ b/chart.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"fmt"
+	"image/color"
+
+	"github.com/martinlehoux/biking_home/mountain_pass"
+	"github.com/martinlehoux/biking_home/ride"
+	"github.com/martinlehoux/kagamigo/kcore"
+	"gonum.org/v1/plot"
+	"gonum.org/v1/plot/plotter"
+	"gonum.org/v1/plot/vg"
+)
+
+func renderChart(r ride.Ride, climbs []ride.Climb, crossings []mountain_pass.Crossing, output string) {
+	p := plot.New()
+	p.Title.Text = "Ride profile"
+	p.X.Label.Text = "Distance (km)"
+	p.Y.Label.Text = "Elevation (m)"
+
+	maxElev := 0.0
+	elevation := make(plotter.XYs, len(r.Points()))
+	for i, point := range r.Points() {
+		elevation[i].X = point.DistanceM / 1000
+		elevation[i].Y = point.ElevationM
+		if point.ElevationM > maxElev {
+			maxElev = point.ElevationM
+		}
+	}
+
+	for _, climb := range climbs {
+		x0 := climb.Start().DistanceM / 1000
+		x1 := climb.End().DistanceM / 1000
+		fill, err := plotter.NewPolygon(plotter.XYs{
+			{X: x0, Y: 0},
+			{X: x1, Y: 0},
+			{X: x1, Y: maxElev},
+			{X: x0, Y: maxElev},
+		})
+		kcore.Expect(err, "failed to create climb band")
+		fill.Color = color.RGBA{R: 230, G: 160, B: 0, A: 70}
+		fill.LineStyle.Width = 0
+		p.Add(fill)
+		p.Add(plotLabels(plotter.XY{X: (x0 + x1) / 2, Y: climb.Top().ElevationM * 1.01}, climbLabel(climb)))
+	}
+
+	for _, crossing := range crossings {
+		x := crossing.RideDistanceM / 1000
+		line, err := plotter.NewLine(plotter.XYs{
+			{X: x, Y: 0},
+			{X: x, Y: maxElev},
+		})
+		kcore.Expect(err, "failed to create pass marker")
+		line.LineStyle.Dashes = []vg.Length{vg.Points(4), vg.Points(2)}
+		p.Add(line)
+		p.Add(plotLabels(plotter.XY{X: x, Y: maxElev * 0.96},
+			fmt.Sprintf("%s %dm", crossing.Pass.Name, crossing.Pass.Elevation)))
+	}
+
+	elevLine, err := plotter.NewLine(elevation)
+	kcore.Expect(err, "failed to create elevation line")
+	p.Add(elevLine)
+
+	kcore.Expect(p.Save(10*vg.Inch, 4*vg.Inch, output), "failed to save chart")
+}
+
+func climbLabel(climb ride.Climb) string {
+	if climb.Name != "" {
+		return climb.Name
+	}
+	return fmt.Sprintf("%s %d", ride.Category(climb.Score()), int(climb.Score()))
+}
+
+func plotLabels(xy plotter.XY, label string) *plotter.Labels {
+	labels, err := plotter.NewLabels(plotter.XYLabels{
+		XYs:    plotter.XYs{xy},
+		Labels: []string{label},
+	})
+	kcore.Expect(err, "failed to create labels")
+	return labels
+}