This is a Python library for accessing wave data on cdip.ucsd.edu servers.

Install

To install this tool: downloading/clone the repo, to a folder that is in your python path (i.e., the files should be in <some-folder-in-python-path>/cdip/).

Install the requirements with pip:

pip install -r requirements.txt

Usage

Then, you can use the tool by doing:

import cdip
dat = cdip.get_thredd(134)  # This example gets data from CDIP buoy #34

Here, dat is a data-object wrapper around a NetCDF file that is hosted on CDIP's servers. The NetCDF variables that are in the file are in dat.variables. The wrapper also uses caching to store data locally (see below).

You can view the names of the available variables by doing dat.variables.keys(). You can then view a variables metadata (e.g., 'waveEnergyDensity')by doing:

>>> dat.variables['waveEnergyDensity']
<class 'netCDF4._netCDF4.Variable'>
float32 waveEnergyDensity(waveTime, waveFrequency)
    long_name: band energy density
    units: meter^2 second
    _FillValue: -999.99
    standard_name: sea_surface_wave_variance_spectral_density
    coordinates: metaStationLatitude metaStationLongitude
    grid_mapping: metaGridMapping
    valid_min: 0.0
    ancillary_variables: waveFlagPrimary waveFrequencyFlagPrimary waveFlagSecondary waveFrequencyFlagSecondary
    ncei_name: WAVE ENERGY - SPECTRAL VALUE
unlimited dimensions: 
current shape = (208252, 64)
filling off

To actually pull the data over the network, do:

spec_array = dat.variables['waveEnergyDensity'][:]

This will pull the entire array over, which will take some time, and will eat some disk space in the .cache_data/ folder. Note, however, that this is only the frequency spectrum. If you want the frequency-direction spectrum, you'll need to do:

dirspec = dat.get_dirspec(0)

Note here get_dirspec only works for a single time (in this case the first time-step in the data object). This is because the entire directional spectrum is very large, and it would take a long time to pull all of that data over the network.

Caching

This tool utilizes the DiskCache libary to store data locally after you've pulled it over the network. This data is stored in the .cache_data/ folder. The tool always check is a variable is present in the cache before querying the server. It does not check whether there is new data available. This means that you need to clear the cache to update the data. Delete the files/folder in that folder to clear the cache.