Analyze Data
============
In the third tab of OCEANLYZ GUI, analysis parameters are defined and data analysis is started.
For technical detail visit https://oceanlyz.readthedocs.io
.. figure:: figures/Figure_GUI_Analyze_Data_Tab.png
:width: 1582 px
:height: 987 px
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Figure: Analyze Data tab
Panel 1
-------
Panel 1 contains parameters that should be set for any analysis.
Input data type (InputType='waterlevel')
Define input data type
InputType='waterlevel': Input data is water level or water depth in (m)
If InputType='waterlevel' then OutputType='wave'
InputType='pressure': Input data are water pressure measured by a pressure sensor at sensor depth in (N/m^2)
If InputType='pressure' then OutputType='waterlevel' or OutputType='wave+waterlevel'
Output data type (OutputType='wave')
Define output data type
| OutputType='wave': Calculate wave properties from water level or water depth data
| OutputType='waterlevel': Calculate water level data from water pressure data measured by a pressure sensor
| OutputType='wave+waterlevel': Calculate waves properties and water level data from water pressure data measured by a pressure sensor
Analysis method (AnalysisMethod='spectral')
Analysis method
| AnalysisMethod='spectral': Use spectral analysis method / Fast Fourier Transform
| AnalysisMethod='zerocross': Use zero-crossing method
Number of burst (n_burst=1)
Number of burst(s) in the input file
| n_burst = (total number of data points)/(burst_duration*fs)
| Example:
| Assume data are collected for 6 hours at a sampling frequency of fs=10 Hz
| If data are analyzed at intervals of 30 minutes then there are 12 bursts (6 hours/30 minutes=12 bursts)
| For 12 bursts of data, which each burst has a duration of 30 minutes, and collected at sampling frequency of fs=10 Hz
| burst_duration=(30 min * 60) = 1800 seconds
| total number of data points=(number of burst)*(duration of each burst)*(sampling frequency)
| total number of data points=(n_burst)*(burst_duration)*(fs)
| total number of data points=12 * 1800 * 10
Duration of each burst (burst_duration=1024)
Duration time that data collected in each burst in (second)
Sampling frequency (fs=2)
Sampling frequency that data are collected at in (Hz)
Panel 2
-------
Panel 2 contains parameters that are required for spectral analysis.
In other words, these parameters are required only if analysis method is set to spectral.
Minimum frequency cut-off (fmin=0.05)
Minimum frequency to cut off the spectrum below that, i.e. where ffmax, in (Hz)
| Results with frequency f>fmax will be removed from analysis
| It should be between 0 and (fs/2)
| It is a simple low pass filter
| Only required if AnalysisMethod='spectral'
Panel 3
-------
Panel 3 contains parameters that are required for pressure data analysis.
In other words, these parameters are required only if input data type is set to pressure.
fmaxpcorr calculation method (fmaxpcorrCalcMethod='auto')
Define if to calculate fmaxpcorr and ftail or to use user defined
| fmaxpcorrCalcMethod='user': use user defined value for fmaxpcorr
| fmaxpcorrCalcMethod='auto': automatically define value for fmaxpcorr
| Only required if InputType='pressure' and AnalysisMethod='spectral'
Pressure response factor for (f > fmaxpcorr), (Kpafterfmaxpcorr='constant')
Define a pressure response factor, Kp, value for frequency larger than fmaxpcorr
| Kpafterfmaxpcorr='one': Kp=1 for frequency larger than fmaxpcorr
| Kpafterfmaxpcorr='constant': Kp for f larger than fmaxpcorr stays equal to Kp at fmaxpcorr (constant)
| Kpafterfmaxpcorr='nochange': Kp is not changed for frequency larger than fmaxpcorr (Not implemented yet)
| Only required if InputType='pressure' and AnalysisMethod='spectral'
Minimum frequency for fmaxpcorr (fminpcorr=0.15)
Minimum frequency that automated calculated fmaxpcorr can have if fmaxpcorrCalcMethod='auto' in (Hz)
| If fmaxpcorrCalcMethod='auto', then fmaxpcorr will be checked to be larger or equal to fminpcorr
| It should be between 0 and (fs/2)
| Only required if InputType='pressure' and AnalysisMethod='spectral'
Maximum frequency for fmaxpcorr (fmaxpcorr=0.55)
Maximum frequency for applying pressure attenuation factor in (Hz)
| Pressure attenuation factor is not applied on frequency larger than fmaxpcorr
| It should be between 0 and (fs/2)
| Only required if InputType='pressure' and AnalysisMethod='spectral'
Pressure sensor height from bed (heightfrombed=0.0)
Pressure sensor height from a bed in (m)
Leave heightfrombed=0.0 if data are not measured by a pressure sensor or if a sensor sits on the seabed
| Only required if InputType='pressure'
Panel 4
-------
Panel 4 contains parameters that are optional.
Water density (Rho=1000)
Water density (kg/m^3)
Only required if InputType='pressure'
NFFT (nfft=512)
Define number of data points in discrete Fourier transform
| Should be 2^n
| Results will be reported for frequency range of 0 <= f <= (fs/2) with (nfft/2+1) data points
| Example: If fs=4 Hz and nfft=512, then output frequency has a range of 0 <= f <= 2 with 257 data points
| Only required if AnalysisMethod='spectral'
Separate wind sea and swell waves (SeparateSeaSwell='no')
Define if to separate wind sea and swell waves or not
| SeparateSeaSwell='yes': Does not separate wind sea and swell waves
| SeparateSeaSwell='no': Separates wind sea and swell waves
Maximum swell frequency (fmaxswell=0.25)
Maximum frequency that swell can have (It is about 0.2 in Gulf of Mexico) in (Hz)
| It should be between 0 and (fs/2)
| Only required if SeparateSeaSwell='yes' and AnalysisMethod='spectral'
Minimum swell frequency (fpminswell=0.1)
Minimum frequency that swell can have (it is used for Tpswell calculation) in (Hz)
| It should be between 0 and (fs/2)
| Only required if SeparateSeaSwell='yes' and AnalysisMethod='spectral'
Start Analysis
--------------
To start analysis click Start Analysis button.
Note: depend on the size of data and analysis method, analysis may take a while.