89 lines
1.9 KiB
Go
89 lines
1.9 KiB
Go
package meta
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import (
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"regexp"
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"strconv"
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"github.com/dsoprea/go-exif/v3"
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)
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var GpsCoordsRegexp = regexp.MustCompile("[0-9\\.]+")
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var GpsRefRegexp = regexp.MustCompile("[NSEW]+")
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var GpsFloatRegexp = regexp.MustCompile("[+\\-]?(?:(?:0|[1-9]\\d*)(?:\\.\\d*)?|\\.\\d+)")
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// GpsToLatLng returns the GPS latitude and longitude as float point number.
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func GpsToLatLng(s string) (lat, lng float32) {
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if s == "" {
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return 0, 0
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}
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// Floating point numbers?
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if fl := GpsFloatRegexp.FindAllString(s, -1); len(fl) == 2 {
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lat, _ := strconv.ParseFloat(fl[0], 64)
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lng, _ := strconv.ParseFloat(fl[1], 64)
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return float32(lat), float32(lng)
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}
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// Parse human readable strings.
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co := GpsCoordsRegexp.FindAllString(s, -1)
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re := GpsRefRegexp.FindAllString(s, -1)
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if len(co) != 6 || len(re) != 2 {
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return 0, 0
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}
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latDeg := exif.GpsDegrees{
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Orientation: re[0][0],
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Degrees: GpsCoord(co[0]),
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Minutes: GpsCoord(co[1]),
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Seconds: GpsCoord(co[2]),
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}
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lngDeg := exif.GpsDegrees{
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Orientation: re[1][0],
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Degrees: GpsCoord(co[3]),
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Minutes: GpsCoord(co[4]),
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Seconds: GpsCoord(co[5]),
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}
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return float32(latDeg.Decimal()), float32(lngDeg.Decimal())
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}
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// GpsToDecimal returns the GPS latitude or longitude as decimal float point number.
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func GpsToDecimal(s string) float32 {
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if s == "" {
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return 0
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}
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co := GpsCoordsRegexp.FindAllString(s, -1)
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re := GpsRefRegexp.FindAllString(s, -1)
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if len(co) != 3 || len(re) != 1 {
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return 0
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}
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latDeg := exif.GpsDegrees{
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Orientation: re[0][0],
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Degrees: GpsCoord(co[0]),
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Minutes: GpsCoord(co[1]),
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Seconds: GpsCoord(co[2]),
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}
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return float32(latDeg.Decimal())
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}
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// GpsCoord returns a single GPS coordinate value as floating point number (degree, minute or second).
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func GpsCoord(s string) float64 {
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if s == "" {
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return 0
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}
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result, err := strconv.ParseFloat(s, 64)
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if err != nil {
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log.Debugf("metadata: failed parsing GPS coordinate '%s'", s)
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return 0
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}
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return result
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}
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