Pydap

Pydap is a pure Python library implementing the Data Access Protocol, also known as DODS or OPeNDAP. You can use Pydap as a client to access hundreds of scientific datasets in a transparent and efficient way through the internet; or as a server to easily distribute your data from a variety of formats.

Quickstart

You can install the latest version (3.2) using pip. After installing pip you can install Pydap with this command:

$ pip install Pydap

This will install Pydap together with all the required dependencies. You can now open any remotely served dataset, and Pydap will download the accessed data on-the-fly as needed:

>>> from pydap.client import open_url
>>> dataset = open_url('http://test.opendap.org/dap/data/nc/coads_climatology.nc')
>>> var = dataset['SST']
>>> var.shape
(12, 90, 180)
>>> var.type
<class 'pydap.model.Float32'>
>>> print var[0,10:14,10:14]  # this will download data from the server
<class 'pydap.model.GridType'>
    with data
[[[ -1.26285708e+00  -9.99999979e+33  -9.99999979e+33  -9.99999979e+33]
  [ -7.69166648e-01  -7.79999971e-01  -6.75454497e-01  -5.95714271e-01]
  [  1.28333330e-01  -5.00000156e-02  -6.36363626e-02  -1.41666666e-01]
  [  6.38000011e-01   8.95384610e-01   7.21666634e-01   8.10000002e-01]]]
    and axes
[ 366.]
[-69. -67. -65. -63.]
[ 41.  43.  45.  47.]

For more information, please check the documentation on using Pydap as a client. Pydap also comes with a simple server, implemented as a WSGI application. To use it, you first need to install a data handler:

$ pip install pydap.handlers.netcdf

This will install support for netCDF files; more handlers for different formats are available, if necessary. Now create a directory for your server data:

$ paster create -t pydap myserver

To run the server just issue the command:

$ paster serve ./myserver/server.ini

This will start a standalone server running on http://localhost:8001/, serving netCDF files from ./myserver/data/, similar to the test server at http://test.pydap.org/. Since the server uses the WSGI standard, it can easily be run behind Apache. The server documentation has more information on how to better deploy Pydap.

Help

If you need any help with Pydap, please feel free to send an email to the mailing list.

Indices and tables

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