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Use smoothing algorithm when computing ascent/descent

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This commit is contained in:
Ray Miller 2020-04-30 06:31:58 +01:00
parent 76fa20d0c1
commit 4ae3bcbd37
1 changed files with 43 additions and 9 deletions
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52
pkg/placenames/summarize.go
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@ -63,6 +63,7 @@ type TrackSummary struct {
Finish string
Distance float64
Ascent float64
Descent float64
PointsOfInterest []POI
RefreshmentStops []RefreshmentStop `json:",omitempty"`
}
@ -82,10 +83,10 @@ func (gs *GPXSummarizer) SummarizeTrack(r io.Reader, stops *rtreego.Rtree) (*Tra
}
}
var elevations []float64
var prevPlace string
var prevPlacePoint rtreego.Point
var prevPoint rtreego.Point
var prevHeight float64
var prevStop *cafes.RefreshmentStop
var start rtreego.Point
var dN, dE float64
@ -99,8 +100,8 @@ func (gs *GPXSummarizer) SummarizeTrack(r io.Reader, stops *rtreego.Rtree) (*Tra
if err != nil {
return nil, err
}
elevations = append(elevations, p.Ele)
thisPoint := rtreego.Point{ngCoord.Easting, ngCoord.Northing}
thisHeight := ngCoord.Height
nn, _ := gs.poi.NearestNeighbor(thisPoint).(*NamedBoundary)
if init {
start = thisPoint
@ -108,15 +109,11 @@ func (gs *GPXSummarizer) SummarizeTrack(r io.Reader, stops *rtreego.Rtree) (*Tra
prevPlace = nn.Name
prevPlacePoint = thisPoint
prevPoint = thisPoint
prevHeight = thisHeight
s.PointsOfInterest = append(s.PointsOfInterest, POI{Name: nn.Name, Type: nn.Type, Distance: 0.0})
init = false
continue
}
s.Distance += distance(thisPoint, prevPoint)
if ascent := thisHeight - prevHeight; ascent > 0 {
s.Ascent += ascent
}
dE += thisPoint[0] - start[0]
dN += thisPoint[1] - start[1]
if nn.Contains(thisPoint) && nn.Name != prevPlace && distance(thisPoint, prevPlacePoint) > 0.2 {
@ -136,16 +133,16 @@ func (gs *GPXSummarizer) SummarizeTrack(r io.Reader, stops *rtreego.Rtree) (*Tra
}
}
prevPoint = thisPoint
prevHeight = thisHeight
}
}
}
s.Finish = prevPlace
s.Direction = ComputeDirection(dE, dN)
s.Direction = calcDirection(dE, dN)
s.Ascent, s.Descent = calcUphillDownhill(elevations)
return &s, nil
}
func ComputeDirection(dE, dN float64) string {
func calcDirection(dE, dN float64) string {
if dN == 0 {
if dE >= 0 {
return "east"
@ -182,3 +179,40 @@ func ComputeDirection(dE, dN float64) string {
}
return "west"
}
// calcUphillDownhill calculates uphill/downhill data
// Implementation from https://github.com/ptrv/go-gpx
func calcUphillDownhill(elevations []float64) (float64, float64) {
elevsLen := len(elevations)
if elevsLen == 0 {
return 0.0, 0.0
}
smoothElevations := make([]float64, elevsLen)
for i, elev := range elevations {
var currEle float64
if 0 < i && i < elevsLen-1 {
prevEle := elevations[i-1]
nextEle := elevations[i+1]
currEle = prevEle*0.3 + elev*0.4 + nextEle*0.3
} else {
currEle = elev
}
smoothElevations[i] = currEle
}
var uphill float64
var downhill float64
for i := 1; i < len(smoothElevations); i++ {
d := smoothElevations[i] - smoothElevations[i-1]
if d > 0.0 {
uphill += d
} else {
downhill -= d
}
}
return uphill, downhill
}