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API Reference for Das2DLM - An IDL Downloadable Module

version 0.5, compiled with das2C 51bb8b1, post v2.3.0

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Das2 servers typically provide data relevant to space plasma and magnetospheric physics research. To retrieve data, an HTTP GET request is posted to a das2 server by a client program and a self-describing stream of data values covering the requested time range, at the requested time resolution, is provided in the response body. This software, das2dlm provides extra IDL system routines for sending data requests and reading the responses directly into memory.

Since this DLM wraps the das2C, and to present function names that are distinct from das2pro, all functions and structures have prefix das2c_.

The functions in this DLM fall into the following categories.

Inspecting Servers

• das2c_srclist - Provide a list of data source paths on a das2 server.
• das2c_srcinfo - Provide call parameter information for a given data source on a server (not present in v0.5)

Getting Data

• das2c_readhttp - Issue an HTTP GET query, and save the results

Using Data

• das2c_results - List/Get stored query results
• das2c_datasets - List/Get datasets in a query result
• das2c_dsinfo - Provided human-readable summary of a dataset
• das2c_props - List/Get metadata properties in a dataset or a variable group
• das2c_pdims - List/Get variable groups in a dataset
• das2c_vars - List/Get a variable in a group
• das2c_data - Get data arrays and slices of data arrays from variables

Utilities

• das2c_loglevel - Set the verbosity of messages from das2dlm & das2C
• das2c_free - Free query result memory
• das2c_convert - Convert data from one set of units to another, including epoch units (not present in v0.5)
• das2c_creds - List resource credentials and URL match conditions
• das2c_credset - Set credentials for a given URL match condition
• das2c_credsave - Save credentials to a file (Warning: Local file not encrypted in v0.5)
• das2c_credload - Load credentials from a file (Warning: Local file not encrypted in v0.5)

What you won't find in das2dlm are plotting functions. IDL provides a rich plotting infrastructure. It is the purpose of this module to get data to you so that you can plot it however you like. That said, a module is best illustrated in context, so a couple of full plotting examples are included.

• ex01_juno_waves_survey.pro - Plotting Juno/Waves Survey data
• ex02_cassini_fce_ephem.pro - Plotting Cassini/MAG E. Cyclotron with location

For a narrative tutorial, see the Usage section in README.md.

Author's note: If you happen to use IDL for space-physics research, I hope das2dlm is useful for you. Feel free to open an issue for any problems you detect, or feature requests. If you feel the discussions section for the repository should be opened, enter that request as an issue.

Thanks for using das2dlm :-)