func tagDegrees(tag *tiff.Tag) (float64, error) {
switch tag.Format() {
case tiff.RatVal:
// The usual case, according to the Exif spec
// (http://www.kodak.com/global/plugins/acrobat/en/service/digCam/exifStandard2.pdf,
// sec 4.6.6, p. 52 et seq.)
v, err := parse3Rat2(tag)
if err != nil {
return 0.0, err
}
return v[0] + v[1]/60 + v[2]/3600.0, nil
case tiff.StringVal:
// Encountered this weird case with a panorama picture taken with a HTC phone
s, err := tag.StringVal()
if err != nil {
return 0.0, err
}
return parseTagDegreesString(s)
default:
// don't know how to parse value, give up
return 0.0, fmt.Errorf("Malformed EXIF Tag Degrees")
}
}
