The formula syntax below can be used to add calculated variables when loading data:

  • In the upload screen in Njord Player or Njord Analytics
  • In Njord Analytics, modify already uploaded data by selecting the uploaded data segment (Data section), and select Process
  • In Njord Analytics, configure one or more formulas to be applied every time data is uploaded to a certain boat. Set this up under Boat - Settings - Process


Heading - COGDifference between Heading and COG
DELTAPERSEC(UNWRAP(Heading))Rate of turn in degrees per second
DELTAPERSEC(BoatSpeed) * 60Acceleration in knots per minute
BoatSpeed / -(FILTER(DELTASEC(BoatSpeed, 10), DELTASEC(BoatSpeed, 10) < 0) / 10)When decelerating, how many seconds to zero knots at current 10 second deceleration average
INTERPOLATED(SERIES("2022-10-01T08:00+02:00", 10, "2022-10-01T11:00+02:00", 14))This could be TWS rising from 10 kts at 8 am to 14 kts at 11 am, for example


<Less thanTo be used with FILTER()
<=Less than equalTo be used with FILTER()
>Greater thanTo be used with FILTER()
>=Greater than equalTo be used with FILTER()
==EqualsTo be used with FILTER()
!=Not equalsTo be used with FILTER()
&Logical andTo be used with FILTER()
\|Logical orTo be used with FILTER()
!NegateTo be used with FILTER()


ABS(value)Absolute of value / remove sign
MIN(value1, value2)Minimum of two values
MAX(value1, value2)Maximum of two values
MOD(a, n)Modulo operation
SIN(value)Sine of value (which is expected to be in degrees)
COS(value)Cosine of value (which is expected to be in degrees)
FILTERPORT(value)Retains the value only on port tack (AWA between -170 and -10)
FILTERSTBD(value)Retains the value only on starboard tack (AWA between 10 and 170)
COALESCE(value1, value2)Choose value1 if it's not empty, else value2
SELECTPORTSTBD(valuePort, valueStbd)Select valuePort when sailing on port tack, valueStbd on starboard tack
UNWRAP(value)Removes wrap at 0/360 degrees, instead expands value below 0 or above 360 as needed for safe calculations
SHIFT(value, rows)Shifts value (series) by given number of rows
SHIFTSEC(value, seconds)Shifts value (series) by given number of seconds
DELTASEC(value, seconds)Delta of value compared to second seconds ago
DELTAPERSEC(value)Delta of value compared to previous datapoint, divided by number of seconds since last datapoint
ROLLINGMEAN(value, seconds)Rolling mean over second seconds
ROLLINGSUM(value, seconds)Rolling sum over second seconds
FILTER(value, mask)Filters value using the given mask, returning empty value where the mask is false
INTERPOLATED(value)Fill blanks between values by linear interpolation
INTERPOLATEDBEARING(value)Fill blanks between values by linear interpolation, correctly handling 0/360 degree wrap around
SERIES(time1, value1, time2, value2, ...)Produces a data series with the given values at the given times. Write times in ISO 8601 format with quotes, like "2022-10-01T10:00+02:00". Use with INTERPOLATED().

Note: all function names are case insensitive and may be written in lower case too.