Add experimental tool for condensing POI.

cmd/condense/main.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/ray1729/gpx-utils/pkg/placenames"
+)
+
+func main() {
+	log.SetFlags(0)
+	maxPOI := flag.Int("max-poi", 0, "Maximum number of points of interest")
+	minDist := flag.Float64("min-dist", 0, "Minimum distance between points of interest")
+	flag.Parse()
+	if flag.NArg() != 1 {
+		log.Fatalf("Usage: %s [--max-poi=N] ANALYSIS.json", os.Args[0])
+	}
+	summary, err := readTrackSummary(flag.Arg(0))
+	if err != nil {
+		log.Fatal(err)
+	}
+	poi := summary.PointsOfInterest
+	if *minDist > 0 {
+		poi = condenseMinDist(poi, *minDist)
+	}
+	if *maxPOI > 0 {
+		poi = condenseMaxPoi(summary.PointsOfInterest, *maxPOI)
+	}
+	result := make([]string, len(poi))
+	for i, x := range poi {
+		result[i] = x.Name
+	}
+	fmt.Println(strings.Join(result, ", "))
+}
+
+func readTrackSummary(filename string) (*placenames.TrackSummary, error) {
+	log.Println("Reading summary from", filename)
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	var summary placenames.TrackSummary
+	err = json.Unmarshal(data, &summary)
+	if err != nil {
+		return nil, err
+	}
+	return &summary, nil
+}
+
+var locationTypePriority = map[string]int{
+	"City":    5,
+	"Town":    4,
+	"Village": 3,
+	"Hamlet":  2,
+}
+
+func condenseMinDist(xs []placenames.POI, minDist float64) []placenames.POI {
+	log.Printf("Condensing by min distance %f", minDist)
+	cont := true
+	for cont {
+		cont = false
+		for i := 0; i < len(xs)-1; i++ {
+			if xs[i+1].Distance-xs[i].Distance < minDist {
+				p1 := locationTypePriority[xs[i].Type]
+				p2 := locationTypePriority[xs[i+1].Type]
+				if i == 0 || p2 < p1 {
+					xs = deleteElement(xs, i+1)
+					cont = true
+					break
+				}
+			}
+		}
+	}
+	return xs
+}
+
+func condenseMaxPoi(xs []placenames.POI, maxPoi int) []placenames.POI {
+	log.Printf("Condensing %d to %d points", len(xs), maxPoi)
+	for len(xs) > maxPoi {
+		var minI int
+		var minD float64
+		for i := 0; i < len(xs)-1; i++ {
+			d := xs[i+1].Distance - xs[i].Distance
+			if i == 0 || d < minD {
+				minI = i
+				minD = d
+			}
+		}
+		p1 := locationTypePriority[xs[minI].Type]
+		p2 := locationTypePriority[xs[minI+1].Type]
+		if minI == 0 || p2 < p1 {
+			xs = deleteElement(xs, minI+1)
+			continue
+		}
+		if minI == len(xs)-2 || p1 < p2 {
+			xs = deleteElement(xs, minI)
+			continue
+		}
+		// p1 == p2
+		d1 := xs[minI].Distance - xs[minI-1].Distance
+		d2 := xs[minI+1].Distance - xs[minI].Distance
+		if d1 < d2 {
+			xs = deleteElement(xs, minI)
+		} else {
+			xs = deleteElement(xs, minI+1)
+		}
+	}
+	return xs
+}
+
+func deleteElement(xs []placenames.POI, i int) []placenames.POI {
+	log.Printf("Deleting %s (%0.1f)", xs[i].Name, xs[i].Distance)
+	return append(xs[0:i], xs[i+1:]...)
+}