randy
a0476f1204
TrackStats.build_profile now also computes elapsed_secs per point (relative to the first known timestamp), alongside the existing cumulative distance. Point x-positions stay distance-based either way — only the shared axis strip's 5 tick labels (and the tooltip) switch between the two, so toggling is a cheap re-render rather than rebuilding the charts. The toggle only appears when a track actually has elapsed-time data to switch to.
72 lines
2.7 KiB
Ruby
72 lines
2.7 KiB
Ruby
module Maptool
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# Distance/elevation-gain/duration for a track, shared by Gpx and Fit so
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# neither has its own copy of the haversine formula.
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module TrackStats
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EARTH_RADIUS_METERS = 6_371_000
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# `coordinates`: array of [lon, lat] or [lon, lat, ele]. `times`: a
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# parallel array of Time (or nil where unknown) — only its first and
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# last non-nil entries matter, so gaps in the middle are fine.
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def self.compute(coordinates, times: [])
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distance = 0.0
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elevation_gain = 0.0
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coordinates.each_cons(2) do |(lon1, lat1, ele1), (lon2, lat2, ele2)|
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distance += haversine(lat1, lon1, lat2, lon2)
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elevation_gain += ele2 - ele1 if ele1 && ele2 && ele2 > ele1
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end
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known_times = times.compact
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duration = known_times.size >= 2 ? (known_times.last - known_times.first).to_i : nil
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{
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"distance_meters" => distance.round(1),
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"elevation_gain_meters" => elevation_gain.positive? ? elevation_gain.round(1) : nil,
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"duration_secs" => duration,
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"point_count" => coordinates.size,
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}
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end
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# One entry per coordinate, for the profile chart: cumulative distance
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# (computed the same way for every format, rather than trusting a
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# device's own odometer field — keeps a GPX and a FIT file directly
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# comparable), elapsed time since the first known timestamp, elevation,
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# and whatever per-point extras (speed/cadence/heart rate) the caller
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# has — nil wherever a format/file doesn't carry it.
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# `extras`: array of hashes parallel to `coordinates`, or shorter/empty.
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# `times`: array of Time (or nil) parallel to `coordinates`, or [].
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def self.build_profile(coordinates, times: [], extras: [])
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start_time = times.compact.first
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distance = 0.0
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previous = nil
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coordinates.map.with_index do |(lon, lat, ele), i|
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distance += haversine(previous[1], previous[0], lat, lon) if previous
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previous = [lon, lat]
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extra = extras[i] || {}
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point_time = times[i]
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{
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"distance_meters" => distance.round(1),
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"elapsed_secs" => point_time && start_time ? (point_time - start_time).to_i : nil,
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"elevation_meters" => ele,
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"speed_mps" => extra[:speed_mps],
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"cadence_rpm" => extra[:cadence_rpm],
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"heart_rate_bpm" => extra[:heart_rate_bpm],
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"lon" => lon,
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"lat" => lat,
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}
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end
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end
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def self.haversine(lat1, lon1, lat2, lon2)
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rad = Math::PI / 180
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dlat = (lat2 - lat1) * rad
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dlon = (lon2 - lon1) * rad
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a = (Math.sin(dlat / 2)**2) + (Math.cos(lat1 * rad) * Math.cos(lat2 * rad) * (Math.sin(dlon / 2)**2))
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2 * EARTH_RADIUS_METERS * Math.asin(Math.sqrt(a))
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end
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private_class_method :haversine
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end
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end
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