Don't log unknown locations

nmea/location.go

@@ -0,0 +1,26 @@
+package nmea
+
+import (
+	"strconv"
+	"strings"
+)
+
+type Location struct {
+	Lat float64 `json:"lat"`
+	Lon float64 `json:"lon"`
+}
+
+// ParseLocation parses nmea sentences into Location structures
+func ParseLocation(nmeaSentence string) (l Location) {
+	fields := strings.Split(nmeaSentence, ",")
+
+	if f, err := strconv.ParseFloat(fields[0], 64); err == nil {
+		l.Lat = f
+	}
+
+	if f, err := strconv.ParseFloat(fields[1], 64); err == nil {
+		l.Lon = f
+	}
+
+	return
+}

receiver/nmea_receiver.go

@@ -58,6 +58,12 @@ func handlePacket(buf []byte, rlen int) {
 
 func appendLog(lat, lon float64, nmeaSentence string) {
 	row := fmt.Sprintf("%f,%f,%s\n", lat, lon, nmeaSentence)
+
+	// don't log unknown locations
+	if lat == 0 || lon == 0 {
+		return
+	}
+
 	if _, err := dbFile.WriteString(row); err != nil {
 		log.Println("unable to write to database:", err)
 	}