Conversion formulas
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Coordinates
(1) Degrees, minutes to decimal degrees:
- Decimal degrees = ((degrees x 60) + (minutes)) /60
NB, N, E are positive, S, W are negative in decimal degrees
- Example: 142° 26' E in decimal = ((142 x 60) + 26) /60 = 142.433 decimal degrees
(2) Degrees, minutes, seconds to decimal degrees:
- Decimal degrees = ((degrees x 3600) + (minutes x 60) + (seconds)) /3600
- Example: 142° 26' 04" E in decimal = ((142 x 3600) + (26 x 60) + 4) /3600 = 142.434 decimal degrees
NB, N, E are positive, S, W are negative in decimal degrees
Note, OBIS also has fields for "Coordinate Precision" and (if relevant), "Start/End Coordinate Precision", with units of meters. The function of these fields is to allow a location to be expressed as a central point plus a radius of uncertainty, e.g. where the original locality description is imprecise (for further information, refer the georeferencing page on this site).
Time
(1) Hours, minutes after midnight to decimal hours:
- Decimal hours = ((hours after midnight x 60) + (minutes)) /60
- Example: 2:15 pm (1415) = ((14x60) + 15) /60 = 14.25 decimal hours
NB, OBIS times are quoted as local time, so if original times are in UTC they should be adjusted by the relevant number of hours for the local time zone
(2) Hours, minutes, seconds after midnight to decimal hours:
- Decimal hours = ((hours after midnight x 3600) + (minutes x 60) + (seconds)) /3600
- Example: 2:15:10 pm = ((14x3600) + (15 x 60) + 10) /3600 = 14.253 decimal hours
NB, OBIS times are quoted as local time, so if original times are in UTC they should be adjusted by the relevant number of hours for the local time zone.
Last modified 29-09-2005