EZL Toolbar

The EZL Toolbar buttons provide access to important commonly-used tasks.

Cache - This button allows you to manually cache (store in memory) the current data set, providing you with a backup for later re-use. This can be a great time-saver in the event of mistaken data operations - accidental over-smoothing, for example. You should try to get in the habit of caching your data before performing operations. Doing so will spare you the frustration of having to rework your steps if you're involved in a lengthy process and make a mistake. The cache is automatically initialized when you first load a data file. So if you do forget to cache your data, you can always revert back to the original state.

Clicking the cache button will provide a submenu with options to either cache the current data set or to retrieve an existing data set. The cache has storage for only one data set. Caching a data set will replace the existing set, if one already exists.

The equivalent command is "cache" to store data, and "cacheretrieve" (or "cacher" for short) to retrieve stored data.

Statistics - Clicking this button will compute a set of common statistics for all the curves in the currently active plotter. The results will be displayed in the Command Window.

The equivalent command is "stats".

Trim Outliers - This button is used to automatically remove data outliers. Outlier determination is based on the standard deviation of the data. With a curve plotted, clicking this button will present a submenu with the following options: 1σ, 2σ, 3σ, and nσ. Selecting one of these will remove all points with absolute values which exceed 1 standard deviation, 2 standard deviations, 3 standard deviations, or n standard deviations from the mean, respectively. Choosing nσ allows you to specify a value for n. If verbose-mode is enabled the statistical results will be displayed in the command window. Example:

> C1: σ = 1.0008, μ = 0.000404752, Upper Bound = 1.0012, Lower Bound = -1.00039

  C1 Trimmed: 317138 points (31.714%).

  Total trimmed: 317138 points (31.7138%).

When multiple curves are plotted, the Trim Outliers button will allow you to operate on each curve independently or to treat all curves as a single data set. In the latter case, the standard deviation and mean calculations will include all data from all plotted curves and will remove points based on those values. Example:

> Concatenated data: σ = 0.98657, μ = 0.0012, Upper Bound = 0.9873, Lower Bound = -0.9851

  C1 Trimmed: 161274 points (32.339%).

  C2 Trimmed: 160469 points (32.176%).

  Total trimmed: 321743 points (32.2573%).

The equivalent command is "trimoutliers" (or "trim" for short).

Crop Tool - This button toggles the crop mode on or off enabling you to manually trim outliers or discard unwanted data points. When this mode is off, using your mouse to draw a box around a selection of data zooms-in on the data. This is done internally by changing the x and y-axis scales to the dimensions represented by the top-left and bottom-right corners of the drawn box. The data which is no longer visible (i.e. points which are outside of the new scale) are not thrown away; they still exists for all operations and statistical calculations, they are simply no longer in view. However, when the crop mode is on the act of drawing a box around data (we call this "drawing a rubber band") does discard all data which falls out of view. This tool is therefore very useful for quickly removing unwanted data points, or for shortening large data sets. Simply draw a rubber band around the data you wish to keep; everything outside of the rubber band is removed and the plot automatically rescales.

Note that when you click on the plot to begin drawing a rubber band, and crop mode is on, a scissors icon will follow the mouse pointer to remind you that you are in fact in crop mode, and not zoom mode. If you mistakenly crop data where you intended to zoom, type "undo" or click the undo button.

Eraser Tool - The eraser tool is the counter-part to the crop tool. In this mode, all data points encapsulated by the rubber band are discarded and points outside the rubber band are retained. So, it behaves in a manner opposite of the crop tool.

Selection Tool - The selection tool is mix between the crop tool and the eraser tool. Drawing a rubber band around a section of data will remove the encapsulated data points from their parent curve, but instead of discarding the points, they will form a new curve.

Undo - EZL provides you with two types of data caches: the User Cache, which is accessed by you (via the Cache toolbar button, or the "cache" command), and the Auto Cache, which is automatically populated whenever you perform an operation which modifies the current data set. As is the case with the User Cache, the Auto Cache is only one deep. Unlike the User Cache, the Auto Cache is emptied upon retrieval thus restoring the used memory back to the program.

The equivalent command is "undo".

Snap-To - This toggle button becomes available when mouse pointer tracking (accessed by going to Toolsets→Pointer) is enabled. Mouse tracking displays the coordinates of the mouse pointer's position within the plot. When this mode is off the displayed coordinates do not necessarily correspond to any particular point within the plotted data curves, but only to the plot's coordinate system itself. However, when this button is toggled on, the displayed coordinates will snap to the curve's point which is closest to the pointer's current position. An animation will hover over the chosen point, to indicate which coordinate is being display.

If more than one curve is plotted, you will be asked to choose the curve of interest upon enabling this feature.

In order to find the point closest to the mouse pointer, EZL must convert every data point to corresponding pixel locations and then compute Pythagorean distances from the current mouse position to each of the locations. And it must do this for every movement of the mouse. This is a computationally expensive procedure. Therefore, for very large data sets you may experience lag in graphics refresh.

Rescale - This button provides a convenient way to rescale the plotter to show all the plotted data. It essentially removes any zoom settings or mouse-wheel scrolls.

The equivalent command is "rescale".

Zoom-In - Each time a rubber band is drawn to zoom in or out, the resulting zoom span and range (zoom setting) is saved for later reuse. This button becomes available when a zoom-in setting is available.

Zoom-Out - As with the zoom-out button, this button becomes available when a zoom-out setting is available.

Abort - The Abort toolbar button is displayed during Allan Deviation computations. Because the Allan Deviation is a CPU intensive algorithm (for All Tau calculations) it can take quite a while for large data sets. This button stops the calculation and displays any results which were computed prior to the abort.

Future versions of EZL will use this button for other potentially long wait-time processes, such as data file loading.