# usage: awk -f GPX2OSM.awk gpx-input-file  >  osm-output-file

BEGIN {
    FS = "[ \"<>]"
    node_id = 0
    way_id = 0
    printf "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"
    printf "<osm version=\"0.6\" generator=\"awk\">"
}

/<wpt / {
    lat = ""; lon = ""
    for (i = 1; i <= NF; i++) {
        if ($i ~ /lat/) {
            lat = $(i+1)
        }
        if ($i ~ /lon/) {
            lon = $(i+1)
        }
    }
    node_id++
    printf "  <node id=\"%d\" lat=\"%s\" lon=\"%s\" />\n", node_id, lat, lon
}

/<trkpt / {
    lat = ""; lon = ""
    for (i = 1; i <= NF; i++) {
		# print i ":" $i ":" $(i+1) ":"
        if ($i ~ /lat/) {
            lat = $(i+1)
        }
        if ($i ~ /lon/) {
            lon = $(i+1)
        }
    }
    node_id++
    nodes_in_way[node_count++] = node_id
    printf "  <node id=\"%d\" lat=\"%s\" lon=\"%s\" />\n", node_id, lat, lon
}

/<trk>/ {
    way_id++
    node_count = 0
}

/<\/trk>/ {
    if (node_count > 0) {
        printf "  <way id=\"-%d\" >\n", way_id
        for (i = 0; i < node_count; i++) {
            printf "    <nd ref=\"%d\"/>\n", nodes_in_way[i]
        }
		printf "  <tag k=\"track\" v=\"track\"/>\n"
        printf "  </way>"
    }
}

END {
    print "</osm>"
}