class TimeSeriesMeasurement

Represents a single estimated (interpolated or extrapolated) measurement from a time series operand passed into the Code operator. Each item in the window_measurements list (an attribute of the OperandInput class) is an object of the TimeSeriesMeasurement class when the operand is a time series variable. The measurement attribute of OperandInput will also return a TimeSeriesMeasurement object in this case.

The TimeSeriesMeasurement class is available from the Echoview Python package.

Attributes

Attribute

Description

type

An object of the MeasurementType class.

index

The index of the measurement in the window_measurements list (not an index into the original time series variable).

datetime

The timestamp of the estimated measurement as a Python datetime object (aligned to the ping time from Operand 1).

gps_distance

Distance along the survey track at the specified time, based on GPS data (nautical miles).

gps_latitude

Latitude at the specified time (decimal degrees).

gps_longitude

Longitude at the specified time (decimal degrees).

vl_distance

Distance along the survey track at the specified time, based on vessel logs (nautical miles).

speed

Vessel speed at the specified time, in knots.

heading

Vessel heading at the specified time, in degrees.

status

The quality of the time series measurement, as a TimeSeriesStatus enum.

value

The interpolated or extrapolated value of the time series variable at the specified time.

Note: Values in a TimeSeriesMeasurement are estimated using the time series operand’s selected or inherent estimation method (linear, circular, or stepped). Times are aligned to the ping times of Operand 1, and may not coincide with any single stored sample in the source time series (both datetime and value can differ from native samples). For circular estimation, the operand may use 0–360° or –180–180° wrapping as configured.

Methods

cal(name)

The Code operator may query a time series' calibration by using this to return the calibration value for the requested entry by the calibration name, for example cal('PulseDuration'). Currently, sounder detected lines may have calibration values.

Note:

If no calibration value exists with the specified calibration name, Echoview generally uses a default value. In addition, where there is:

  • no TransducerGain: Echoview returns TransducerGain if it is set.
  • no TRFactor: the KaijoTrFactor is used if it is set otherwise TRFactor is determined using the Simrad EK60 power to Sv and TS equation.
  • no AbsorptionCoefficient: when Francois & Garrison (1982) values are available, the calculation for the center frequency is evaluated and used.

See also

OperandInput class
Ping class
About the Code operator
Using the Code operator