The CDAWeb is a center at NASA/Goddard which stores data from Earth-orbiting missions.

dataset Structured set of numbers having scientific meaning. This contains both dependent and independent parameters, such an array Density values which are a function of Time: Density[Time]

metadata Data describing the data. For example, the data are numbers representing Density which is a function of Time; and but metadata might include the labels "Density" and "Time" and which spacecraft collected it. Metadata is often split into "use" and "discovery" metadata, where use would be things you need to know to use the data, such as the units and axis labels; while discovery is what was used to find the data, such as the spacecraft and instrument name.

QDataSet Autoplot's method for representing a dataset, or data model. It allows representing trivial data such as the scalar "6.2", Density tabulated as a function of time, spectrograms, or complex joins of tables. See QDataSet.

rank the number of indices of a QDataSet. E.g. Density[Time] is a rank 1 dataset with the one index corresponding to time; Flux[Time,Energy] is a rank 2 dataset.

dataset geometry the structure of the dataset, including its rank and dimension lengths.

join dataset like an array of datasets, where each of the elements has a dataset with like properties. For example, an instrument that has several sampling modes would produce this sort of data. See ragged dataset.

simple bundle dataset rank N dataset containing a number of rank N-1 datasets. For example, ds= bundle( time, density, temperature ) where time, density and temperature results in a rank 2 bundle dataset, with ds[m,3] elements.

qube Constraint to arrays that each element is the same thing, e.g. a 4x5 Array is 4 5-element arrays. This is opposed to Java arrays which are the more general array of arrays, where each array can have different length ("ragged arrays" or "city skyline"). In QDataSet, this extends to the metadata, where each element has the same type of metadata. Most formats are constrained to qubes. For example, any variable in a CDF file is a qube. The das2server

ragged dataset Opposite of a qube dataset, where each slice of a join may have a different geometry (e.g. 1st is 1144 by 43, 2nd is 1144 by 18, etc.)

interface vs implementation An interface is how you interact with an object, and the implementation is how the object is coded to provide that interface.

backing or backed The native data store for the dataset. Since a QDataSet is an interface, clients needn't worry about the mechanics of the data storage in arrays or memory-mapped files. For example, a 2-index QDataSet may be backed by a single-index double array or by a file that has been memory-mapped into Java.

mutable or writable QDataSets are immutable, meaning that once created they cannot be modified. However, it is common that functions will return versions of the data that can be modified. Further complicating things, Jython's datasets are often mutable, and duck typing means that it's easy for users to assume that all datasets are mutable.

buckshot data data with the independent data distributed randomly. This is opposed to gridded data, where the independent data is taken at somewhat regular intervals.

gridded data data with the independent data distributed regularly, such as in the rows and columns of a spectrogram.

context term used preserve information, as in "out of context." For example if a spectrogram is sliced at an energy, then the slice location (e.g. 300eV) is the context for the new dataset, and it can be displayed alongside the data so that the data is not presented out of context. Similarly, the Plot objects have a context property, which allows them to control a context, typically a timerange when comparing two slices of a time series, so no time axis is visible.

timerange an interval of time, formatted and parsed in concise string messages, like "2016-05-05" for May 5, 2016. See [more about times]. These are a special case of DatumRange, which is an interval in a physical dimension, with a minimum to a maximum.

flatten take arbitrary dataset and make in into rank 2 ds[n,m] where n is the total number of points, and m is the number of physical dimensions.

grid take flattened data and attempt to form gridded data in a rank 2,3, or 4 qube.

slice extract the elements of one of the dimensions reducing the rank by 1. For example slice0(0) takes ds[3,4,5] and returns ds[4,5]

CDF Common Data Format developed at NASA

HDF5 Hierarchical Data Format is a binary format with abstractions like named multi-dimensional qube arrays of data.

NetCDF Data Format now based on HDF5 that is used in earth sciences.

ASCII Table A text file with records delimited by new lines, and fields within each record delimited by spaces, commas or column position. Each record must contain the same number of records, and those that do not are considered to be comment lines and are ignored. The first line can contain field labels and units.

OpenDAP Not really a format but a protocol for communicating data over the web.

Rich ASCII Ascii file with special JSON metadata at the beginning, providing additional metadata and data relationships similar to CDF.

Rich PNG PNGs created by Autoplot (and possibly other systems) that contains axis transformations and labels in a roughly 1 KB of additional size. This allows users to "grep" for axis labels and use the pngwalk tool to look up coordinates. [1]

URI Uniform resource identifier, and in Autoplot these specifically refer to data sets. For example, vap+cdf:http://autoplot.org/data/autoplot.cdf?BGSEc refers to data in a NASA CDF file, and vap+inline:linspace(0,5PI,100)&sin(linspace(0,5PI,100)) refers to a sine wave.

file is used to represent a local file or anything that could be downloaded and used as a file. For example, http://autoplot.org/data/2010_061_17_41_40.txt is a file.

folder is a container for files. For example, http://autoplot.org/data/ is a folder.

filesystem a heirarchy of folders and the files contained within. Autoplot is able to treat a local folder and http location (http://autoplot.org/data/) as filesystems. Supported filesystem types include FTP, HTTP, SFTP, and .zip files.

switch Like an IDL keyword, switch is used to refer to named parameters in URIs and Python function calls. For example, in "http://autoplot.org/data/2010_061_17_41_40.txt?column=field8&where=field8.gt(1e-16)" the switch "where" is used to extract a subset of the data.

vap file an xml file containing an Autoplot canvas configuration, like a .doc file is to Microsoft Word or .html is to Firefox.

events file ASCII file containing three columns: start time, end time, and event label. These are used to identify orbits, control PNG Walk generation, and mark events. (See events list.)

DOM Taken from web terminology, it is the configuration of the application.

canvas the 2-D space on which the application resides.

plot a rectangular areas using two axes to form a 2-D space, and a third colorbar axis controlling data to color.

plotElement controls how data is painted onto a plot using the plot's axes, keeping track of the data, plot, and render type.

property a controllable aspect of a plot, plotElement, or any DOM component.

binding a connection between two properties of the DOM. For example, each plot typically has its x-axis' range property bound to the application timeRange property, so a stack of plots all show the same time range.

connector component that relates two axes, drawing lines to show where they reside with respect to one another. For example, the "context overview" shows the top plot as a short, more detailed interval, connected to a longer interval plot below.

renderer is the Das2 component that paints data onto plot. Examples include "spectrogram" and "eventsBar". Autoplot picks the renderer appropriate for the data, but the scientist (or script) can override this. This shows rendering types: http://autoplot.org/developer.renderTypes

keyword See named parameter. IDL uses this name for its similar idiom, and keyword is sometimes used as a synonym.

switch See named parameter. Unix commands uses this name for its similar idiom, and switch was used for a while to describe Jython named parameters.

named parameter a Jython function parameter which is defined by name rather than position, similar to IDL keywords. For example, in "plot( ds, index=1 )" index is a named parameter, and ds is a positional parameter.

browse trigger code which is triggered by a URI in the DataSetSelector with the "inspect" button pressed.

inspect button folder and magnifier.

play button green triangle pointed west.

GUI graphical user interface.

data source editor Editor provided for a particular data source, such as CDF files, which edits URIs.

These are workgroup and institution references are found in documentation and bug tickets. LANL Los Alamos National Labs. Los Alamos, New Mexico, USA

NMC New Mexico Consortium. Los Alamos, New Mexico, USA

GMU George Mason University.

APL Applied Physics Labs. Laurel, Maryland, USA

ESA European Space Agency

NASA National Aeronautics and Space Administration. Greenbelt, MD

U. Iowa The University of Iowa, Iowa City, Iowa, USA

UNH University of New Hampshire. Durham, New Hampshire

Aerospace The Aerospace Corporation.

UCLA University of California, Los Angeles, California, USA

SWRi Southwest Research Institute.

CDAWeb The workgroup at NASA/Goddard which created and manages the CDF file specification and data sets.

TSB Time Series Browse, the capability for a data source to span long time intervals (years) but typically browsing is done by day. Autoplot uses the TimeSeriesBrowse capability to query for new time ranges. Datasets can also have a resolution which will load a reduced version of the data, and will always have an intrinsic resolution which is the limit of how fine the resolution can be.

TCA Time Correlated Annotations are das2-specific name for additional information added to x-axis ticks when browsing through time. This is often called ephemeris data. See http://autoplot.org/cookbook#Add_Axis_Annotations for how these are added.

Axis Annotations ephemeris data attached to the x axis major ticks, in addition to the time values at each tick.

Annotations Text which can be attached to plots, data, and the canvas, for adding titles or pointing out features.

Matlab Data analysis software often used in engineering but often in Space Physics as well.

IDL Data analysis software often used in Space Physics and Medicine.

Jython Python implemented in Java. This is the Python Autoplot uses. All Java libraries are available to it, but Python codes such as SciPy are not (yet).

ISO8601 ISO spec for formatting time that everyone should know and we can all agree on, where Year comes first then less significant components follow. For example, 2014-01-01T00:00Z is a well-formatted time. The specification also defines time spans, and this is supported somewhat as well. http://en.wikipedia.org/wiki/ISO_8601

JSON Structured ASCII format, often used where XML shouldn't be used. XML data is all strings with explicit schemes, where JSON is String,Float, and Integer types with duck typing.

gzip Compression format that has the feature that it can be streamed, is freely available, and is supported in most programming environments.

zip file Hierarchical files and folders contained in one file.

jar file a .zip file used to distribute Java software.

jumbojar a jar file containing all the software needed to run the application, which also contains a unix bash script at the beginning of the file, that will launch the software on Linux.

single jar another name used for jumbojars.

human-readable Expression used often in documentation to indicate the result should only be interpreted by humans and never machines. For example, toString output should never be parsed, as it can be changed to improve the human interface.

events list list of time intervals of interest. In Autoplot these ranges are often accompanied with an RGB color and text label. They are used to control the xaxis to jump around to convenient times, enumerate orbit numbers, and to control pngwalk generation.

orbits list a special case of an events list enumerating the orbits of a spacecraft. Typically these are contiguous in time, but need not be.

orbits file special case of a csv or text file, where it is three or four columns, having startTime, endTime, [rgbColor,] label.

orbit time range string encoding a time interval from an orbits file, like "orbit:junoPP:7"

ad-hoc orbit time range orbits time range, with the filename, like "http://das2.org/Orbits/de1.dat"

data mashing the practice of taking several datasets and combining them to create a new dataset. For example, take B magnitude and calculate FCE by dividing, or taking a noisy dataset and filter on a quality index.

dashup the working name for the Autoplot utility for doing data mashing. "Mashup" is the final name.

filters alias for the processes in the process stream. Autoplot allows users to "pipe" data through a set of processes.

process chain better name for the processes applied to the data before plotting. Filters have the problem that one filter type might be to filter data more than 1000.

GUI Graphical user interface, the buttons, text areas, and other components that make and control an application.

Data Source A source of data for Autoplot, namely the software that can take a URI and produce a QDataSet, and often provides GUI controls.

Data Source Editor The GUI used to control URIs for a Data Source.

event an interval in time, often with associated label and color. See events list

event a Java object representing a human action (e.g. button press) or timer expiring.

URI uniform resource identifier, in Autoplot's case identifying a data source and its configation.

Idempotence a function which once applied will always have the same result, like abs or mod, or makeMonotonic.

Dataset "size" and "dimensions" are both used to mean the same thing. "Geometry" refers to the overall structure. The "size" command returns an array of lengths for each dimension of the qube dataset. "ELEMENT_DIMENSIONS" returns an array of lengths as well, and should be renamed "ELEMENT_SIZE". Unfortunately "variables" and "parameters" are used interchangeably. "variable" should refer to a named quantity in a script, and parameter should refer to an interface. A script has parameters which controls variables within. A CDF file has "parameters" but these are also called variables in other contexts.