Working with Plots

In Mira , the term "plot" refers to displaying 1-D ("1-dimensional") data in the form of a 2-D graph. A special type of window exists to display and work with plots, known as a Plot Window. In working with images, plots are often created to show the relationship between image luminance and position, known as a Profile Plot (see example below), but a number of other types of plot are available within the software. Click here to view some examples of plot data.

Plot Types

Mira can create the following plot types from 1-dimensional data:

Comparison of Profile Plot Types


Column or Row Profile

Line Profile

Radial Profile

Uses the Image Cursor to sample pixels


Uses the mouse pointer to sample pixels



Uses Pixel coordinates

Uses World coordinates

Append series from parallel pixel samples



Append series using Copy / Paste

Profile must be parallel to rows or columns




Plot Coordinates

All of the profile plots show image luminance versus position or distance. For these types, Mira also provides the following coordinate system options:

Coordinate Axis:
Luminance Axis:

Luminance is displayed on the vertical axis of a profile plot and the horizontal axis of a histogram plot. The Luminance Axis label includes the units of luminance if the image header contains such information.

Working with Plot Series

A Plot Series is a collection of data points collected together. Usually these collections are related. For example, in a Column Profile plot, a plot series is a single sample of luminance versus position along a single line. A different series might be a sample of points parallel to the first, taken along a different column. Profile plots can show a single plot series or multiple plot series from samples along other lines. When multiple series are displayed in the same Plot Window, they may be visualized in the following ways:

Averaging Adjacent Lines

Adjacent lines (columns or rows) may be combined to form a single line to be plotted. The method of combining is controlled by the Plot Averaging Mode command. The name of the plot appears in the command menu from which the plot is created (see Plotting an Averaged Line).

Plot Preferences and Attributes

Understanding Plot Captions

Caption Above the Plot Box

The Plot Caption is the text above the plot box and below the top window border. The Plot Caption tells you information about what was plotted. In particular, it may list the beginning and ending coordinates in (x,y) form for a Line Profile Plot or it may list the column and row range for a Column Profile or Row Profile plot. Below are some examples that show how to read the column,row range in the plot caption:

Example Regions Listed in the Plot Caption

[125:140, 180:182]

Columns 125 through 140, inclusive and rows 180 through 182, inclusive. This describes 16 columns and 3 rows.

[125:140, 180]

Columns 125 through 140, inclusive and row 180. This describes 16 columns and 1 row.

You can change the plot caption using the Labels page of the Plot Attributes dialog.

Window Caption

The Plot Window caption lists the image name from which the plot was created and gives an abbreviation that describes the type of plot. The plot type is abbreviated and appended to the window caption in square brackets. For example, a Row Plot is signified by [RP] appended to the Plot window caption. These suffixes appear in the window list of the Window menu and in the Multi-tab Interface along the bottom border of Mira's main window.


After using the Windows Copy + Paste protocol to add series to a plot window, the window caption may not accurately reflect the content of the window. You can change the caption using the Plot Attributes command.

Plot Name Suffixes


Column Plot along a single column in one or more images.


Row Plot along a single row in one or more images.


Average Column Plot along an average of parallel columns in one or more images.


Average Row Plot along an average of parallel rows in one or more images.


Line plot along a general direction.


Histogram Plot


Radial Profile Plot


3-D surface or wireframe plot of the rectangular region inside the image cursor.


Pixel Series Plot for pixels in a series of images.


Bit Histogram Plot.

Related Topics

Plot Windows, Plotting Commands, Plot Coordinate System, Plotting an Averaged Line, Working with Plot Series Data, Scatter Plot