The Measurement class in the center

The measurement (meas) is the central object in the pluggable structure of ixdat, and the main interface for user interaction. A measurement is an object of the generalized class Measurement, defined in the measurements module, or an inheriting *TechniqueMeasurement* class defined in a module of the techniques folder (see Techniques: ixdat’s measurement subclasses).

The general pluggable structure is defined by Measurement, connecting every measurement to a reader for importing from text, a backend for saving and loading in ixdat, a plotter for visualization, and an exporter for saving outside of ixdat. Each TechniqueMeasurement class will likely have its own default reader, plotter, and exporter, while an ixdat session will typically work with one backend handled by the db model.

Subclasses for measurement techniques

The TechniqueMeasurement subclasses are structured such that they all inherit basic properties and methods from the Measurement base class. Additionally, classes for related techniques, in particular for combined techniques, inerit from more general other technique classes for shared functionality. The figure below shows this with the ECMSMeasurement subclass inheriting both EC specific methods (e.g.: cycle selection) and MS specific methods (e.g.: gas calibration), as well as providing additional methods relevant for the combined technique (e.g.: EC calibration).

A full list of TechniqueMeasurement classes can be found in Techniques: ixdat’s measurement subclasses.

What’s in a measurement

A measurement is basically a wrapper around a collection of data_series (see The data series structure).

There are several ways of interracting with a measurement’s data_series:

• Most TechniqueMeasurements provide attribute-style access to essential DataSeries and data. For example, ECMeasurement has properties for potential and current series, as well as t, v, and j for data.

• meas.grab() is the canonical way of getting numerical data out of a measurement. Given the name of a ValueSeries, it returns two numpy arrays, t and v where t is the time (wrt meas.tstamp) and v is the value as a function of that time vector. grab takes a series name as its first argument and can also take a tspan argument in which case it cuts the vectors to return data for the specific timespan of the measurement.

• Indexing a measurement with the name of a data series returns that data series, with any time values tstamp’d at meas.tstamp

• The names of the series are available in meas.series_names.

• The raw series are available in meas.series_list.

The measurements module

Here is the full in-line documentation of the measurements module containing the Measurement class.