Graham McIntire
0d2cfb68f1
- Detail panel now reads as an aiming card: "Aim 220° (SW) · clearance +12 ft" with the precise bearing in degrees, plus rover/obstacle elev on a second line - Elevation profile labels swapped from min/max-of-profile to start (rover) and end (station) elevations, since their positions in the chart now match - Map draws a dashed indigo polyline from the candidate to each selected station when a candidate is opened; cleared when the panel closes
56 lines
1.8 KiB
Elixir
56 lines
1.8 KiB
Elixir
defmodule Microwaveprop.Rover.DriveTime do
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@moduledoc """
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Distance, drive-time, and compass-bearing helpers for the rover
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planner. All inputs are degrees / kilometres; no I/O.
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"""
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@earth_radius_km 6371.0
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@avg_speed_kmh 65.0
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@spec haversine_km({float(), float()}, {float(), float()}) :: float()
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def haversine_km({lat1, lon1}, {lat2, lon2}) do
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rlat1 = deg_to_rad(lat1)
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rlat2 = deg_to_rad(lat2)
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dlat = deg_to_rad(lat2 - lat1)
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dlon = deg_to_rad(lon2 - lon1)
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a =
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:math.sin(dlat / 2) ** 2 +
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:math.cos(rlat1) * :math.cos(rlat2) * :math.sin(dlon / 2) ** 2
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2 * @earth_radius_km * :math.asin(:math.sqrt(a))
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end
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@spec drive_min(float()) :: float()
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def drive_min(dist_km) when is_number(dist_km), do: dist_km / @avg_speed_kmh * 60.0
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@spec bearing_compass({float(), float()}, {float(), float()}) :: String.t()
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def bearing_compass(from, to) do
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from |> bearing_deg(to) |> compass_for()
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end
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@spec bearing_deg({float(), float()}, {float(), float()}) :: float()
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def bearing_deg({lat1, lon1}, {lat2, lon2}) do
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rlat1 = deg_to_rad(lat1)
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rlat2 = deg_to_rad(lat2)
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dlon = deg_to_rad(lon2 - lon1)
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y = :math.sin(dlon) * :math.cos(rlat2)
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x = :math.cos(rlat1) * :math.sin(rlat2) - :math.sin(rlat1) * :math.cos(rlat2) * :math.cos(dlon)
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y |> :math.atan2(x) |> rad_to_deg() |> normalize_deg()
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end
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@compass_points {"N", "NE", "E", "SE", "S", "SW", "W", "NW"}
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defp compass_for(bearing) do
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index = bearing |> Kernel.+(22.5) |> div_floor(45.0) |> rem(8)
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elem(@compass_points, index)
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end
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defp div_floor(a, b), do: trunc(a / b)
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defp deg_to_rad(deg), do: deg * :math.pi() / 180.0
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defp rad_to_deg(rad), do: rad * 180.0 / :math.pi()
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defp normalize_deg(deg), do: deg |> Kernel.+(360.0) |> :math.fmod(360.0)
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end
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