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THEMIS SCIENCE WORKING TEAM MEETING Post-AGU Data Visualization Software Larson University of California - Berkeley. Overview. Overview Software Objectives Data Distribution Topic 3. Software Objectives. Code is available to everyone, but not required to analyze data.
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THEMIS SCIENCE • WORKING TEAM MEETING • Post-AGU • Data Visualization • Software • Larson • University of California - Berkeley
Overview • Overview • Software Objectives • Data Distribution • Topic 3
Software Objectives • Code is available to everyone, but not required to analyze data. • IDL based (library of routines –but no main program!). • Command driven. • Separates the tasks of: • Reading files. • Manipulating data • Plotting • Platform independent. Works on: • Solaris • Linux • Windows • MacOSx • Implements automatic file retrieval • Given time interval and data type as input • Relies on well defined directory structure. • Root directory stored as environment variable. • WEB download to local directory cache. (NEW!) • Raw data is easily “extracted”, “manipulated”, “plotted”. • Software maintains track of variables (data quantities). • Can be used for batch mode processing and/or GUIs.
Data Definitions: • Level 0 Data – • Raw files (*.pkt) one per APID. • Not used at all by Scientific community. • Level 1 Data - • CDF (Common Data Files) files (*.cdf) • Contain raw (uncalibrated) data. i.e. counts, DAC units. • Used by many scientists. • Typically requires software to interpret. • Level 2 Data • CDF files – contain physical quantities.
Data / Directory structure • Will be large! (scores of files per day) • Consistent across all platforms. • Software performs automatic file retrieval. • Same Directory hierarchy on WEB and local file system. • Root directory: • WEB • http://sprg.ssl.berkeley.edu/data/themis/ • http://themis.ssl.berkeley.edu/themisdata/ • File Servers (defined by environment variables) • /disks/data/themis (unix systems @ SSL) • Portable laptops: (defined by enironment variables) • C:\data\themis • Directory Hierarchy • Same on all systems below the root directory
Initialization • Done by single routine: “themis_init” • Reads environment variables: • Defaults defined in “themis_environment” • “THEMIS_DATA_DIR” • “THEMIS_REMOTE_HOST_DIR” • Defines system variable “!themis” • idl> themis_init • !themis = THEMISSTR----> • LOCAL_DATA_DIR = 'C:\data\themis\' • REMOTE_DATA_DIR = 'http://sprg.ssl.berkeley.edu/data/themis/' • Data Retrieval Process: • Each data retrieval procedure “knows” the relative location of data files in the directory hierachy. • Software searches first in: LOCAL_DATA_DIR • If not found then it is automatically downloaded at: REMOTE_DATA_DIR and placed in LOCAL_DATA_DIR • Subsequent runs will find files in LOCAL_DATA_DIR. • To disable auto download set REMOTE_DATA_DIR to null string (“”)
Software Usage: • Example 1: Loading ground magnetometer data (ccnv) • From within IDL type: • To load data: • IDL> thm_load_gmag,’ccnv’ • To plot data: • IDL> tplot,’thg_mag_ccnv’
Primary Routines: • Loading Routines: • Thm_load_gmag - ground magnetometer • Thm_load_ask - All Sky Keograms • Thm_load_fgm - Flux Gate magnetometer • Thm_load_scm - Search coil magnetometer • Thm_load_efi - Electric Field Instrument • More to come:
File management: • The user is responsible for cleaning up their own mess. However there is a tool to help: “thm_file_cleanup” will (eventually) be able to delete files in the directory structure based on: • File access time • File modification time • File size