Autoplot is a Java application which can read data from many sources, such as ASCII tables, NASA CDF files, and HDF5 files. It can also read data from data servers, such as the server at NASA/Goddard/CDAWeb, Das2Servers used by the Radio and Plasma Wave Group at the University of Iowa, and servers supporting the HAPI API.

Autoplot identifies data using "URIs", which are one-line strings containing a data source ID and configuration to read the data.
These URIs can be created using the Autoplot application, available at http://autoplot.org/. Data are read into a standard data model, QDataSet, which is easily adapted to Python using the JPype library. Helper procedures from the Autoplot package convert QDataSets into ndarrays.

Autoplot/Python Interface Tools

The Autoplot/Python package is loaded using pip:

> pip install autoplot

Once the package is installed, in Python Autoplot is now accessible.

import autoplot as ap

# Download autoplot.jar if needed and return Python bridge object
ap.init()

# Create Autoplot Data Set.  This object manages loading the data and then containing it until extracted.
apds = ap.APDataSet()

# Set URI
apds.setDataSetURI('http://autoplot.org/data/swe-np.xls?column=data&depend0=dep0')

# Get the data
apds.doGetDataSet()

print(apds.toString())
# http://autoplot.org/data/swe-np.xls?column=data&depend0=dep0
# data: data[dep0=288] (dimensionless)
# dep0: dep0[288] (days since 1899-12-30T00:00:00.000Z) (DEPEND_0)

# Extract data values
vv = ap.to_ndarray(apds, 'data')
tt = ap.to_ndarray(apds, 'dep0')

from matplotlib import pyplot as plt
plt.plot(tt,vv)
plt.show()

Changes are Coming

Over the past few years, Python and the JPype interface have changed and some examples no longer work. The interface was based on IDL and Matlab use, and a more precisely tuned interface for the Python community is needed. (For example addjavapath is a Matlab command and is strange to Python programmers.) This work should be done in 2023. See https://github.com/autoplot/python/wiki/python_reset.

For example, to reformat a remote HDF file to a local ASCII file in Python:

import autoplot as ap
data=ap.getDataSet('http://autoplot.org/autoplot/data/AMSR_E_L3_SeaIce6km_B06_20070307.hdf?SpPolarGrid06km/Data_Fields/SI_06km_SH_89H_ASC')
ap.formatDataSet(data,'file:/tmp/ap/SeaIce6km.txt')

Contact

Jeremy Faden faden@cottagesystems.com

See also https://github.com/autoplot/python/wiki