T4: Graphical
presentation and export of results (1)
This tutorial was created on
MatCalc version 5.23 rel 1.026
license: free
database: mc_sample_fe.tdb
Contents
- Creating a new graphical window
- Introduction to the
variables window
- Modifying the appearance of a plot using 'options'
- Zooming in and displaying x- and y-values
- Exporting a plot as an image and as numerical data
Before starting...
Open the file saved from Tutorial 3 and select the buffer named
'T=400 to 1600°C'.
1. Plotting a graph
To plot numerical results, it is first necessary to create a graphical
window. In the 'View' menu, click
on 'Create
new window'or click on icon.

In the 'Create new window' box which
appears, there is a list of a number of possible window types.
Among these are '(a1)', '(a5)' and
'(a6)', which are the familiar 'output', 'phase
summary' and 'phase
details' windows automatically placed on the screen when
a new workspace file is created.
Select type '(p1) Plot: XY-data' and
click on 'OK'

An empty plot with x- and y-axes appears on the screen. Locate
the 'Variables' window. (If it is not present, right-click in the
toolbar area at the top of the screen and select it from the menu,
or click on 'Show variables window' from the 'View' menu.) Expand
the 'favorites' section by clicking on the small plus-sign to its
left. Then, further expand the section labelled 'F$*' to give the
list shown below.

The syntax 'F$BCC_A2' means 'the
phase fraction of BCC_A2', where
the dollar sign is a separator between the variable 'F' and the
phase to which it applies 'BCC_A2'. In the heading of the list,
'F$*', the asterisk is a wild-card indicating 'all
phases'. Select
'F$*', drag it to the empty plot and drop it.
The plot should appear as shown below:

2. Changing the appearance of the plot
Results from different buffers
The 'Options' window can now be used
to modify the appearance of the plot as required. (Again, if this
is not currently shown, it can be made to appear using the View
menu or the right-click menu in the toolbar area.)

Firstly, note that there is a 'buffer' drop-box. By selecting
one of the other buffers, the contents of the plot can be changed.
The 'default x-data' option (the second line down in the options
window) is set to StepValue, i.e. the value of the stepped variable
used in the stepped equilibrium calculation. Thus, on selecting
the 'C=0 to 1.5 at 500°C' buffer, the x-value changes to carbon
content, and the plot looks like this:

and the plot for the 'C=0 to 1.5 at 800°C' buffer looks like
this:

Changing the format of the temperature-step plot
Select the 'T=400 to 1600°C' buffer
from the buffer drop-box. One of the first things to note is that
the x-axis data does not run from 400 to 1600; this is because
the step value is expressed by default in Kelvin rather than in
Celsius. To change this, double-click on the 'default
x-data' line. A box appears, entitled 'New
value for 'default x-data''. Enter 'T$C' (temperature
in Celsius) in place of 'StepValue'.

The plot can be changed from colour to black-and-white ('b/w') using the
'style sheet' drop box.
The 'plots' section of the options
menu can be expanded using the plus-sign. Below 'plot#0' (the
name of the current plot) is a list of options for this plot:

Title
This is blank by default. Double-click to enter a title, e.g. 'Phase fraction versus temperature for Fe-0.4 wt.%C'.
Legend
This comprises options for the position of the legend and for
the style of the box surrounding it.

Axes
The 'axes' section expands to give options for the 'x-axis', 'y-axis',
'2nd x-axis' and '2nd y-axis' (the latter two are not used in the current
plot).

Double-clicking on the 'title' line will bring up a box entitled
'New value for title'. Enter 'Temperature
[°C]'. In the same
way, change the y-axis title to 'Phase fraction'.
The axis type can be set to either linear or logarithmic. A linear
scale is more suitable for the temperature axis, but a logarithmic
y-axis enables the fractions of minor phases, such as cementite
in this example, to be seen more clearly. Change 'lin' to 'log' for the y-axis.
The automatically assigned minimum y-value on the log-scale may
not be appropriate, so if this is the case, double-click on 'scaling' and replace 'auto' with '0.01..1'. The two numbers are the lower
and upper limits respectively. If one or other of these is missed
off, an automatic value is assigned instead. (For example, using
'0.01..' is sufficient to give a scale from 0.01 to 1, since 1
is the maximum value of F$*).
Grid
This allows gridlines to be added to the plot, and their appearance
to be modified. Change 'disabled' to 'enabled' for 'major-x' and
'major-y' to show major gridlines.

Series
Expanding the 'series' section gives a list of options for each
data-series. The name of the series (as it appears in the legend)
can be changed using 'name'.
The 'locked' option, when set to 'yes', protects the series from
any changes when the contents of the buffer are updated. A locked
series is indicated by an asterisk by the name, if the automatic
name is used.
'Derivative' can be used to display the numerically evaluated
first or second derivative of a series.
The 'x-data' and 'y-data' options
control which data-sets are displayed on the x- and y-axes. If
the 'x-data' is set to 'auto',
the default x-data, as specified above, is used.
The appearance of the plots can be modified by setting 'default
style' to 'no' rather than 'yes',
and then expanding 'line' and
'marker' to give a list of options for
colours, styles, sizes etc.

The image below gives an example of a modified plot.

3. Other plot operations
Zooming areas of the plot
Left-click in the plot area and drag the mouse to draw a rectangular
box. When the mouse button is released, an enlarged version of
the region within the box is shown on the axes. Right-click anywhere
in the plot area to return to the original scale.
Displaying x- and y-values
When moving the mouse pointer on the plot area, a black cross appears with the y- and x-values next to it. The coordinates of the centre of the cross are also shown
on the status bar at the bottom
left of the screen. A larger, red cross can be obtained by pressing the right mouse button.
Exporting data from the plot
Right-clicking in the plot window but outside the area of the
plot itself gives a context menu as shown below.

Click on 'Copy pixmap' to export the
plot as a bitmap file. This can be pasted into any graphical application. 'Copy
data' exports the numerical data from the plot in the form
of tab-separated columns. The data can be imported into a text
editor or a spreadsheet application for further processing.
'Export to PDF' allows to create a ".pdf"-file containing the plot.
To finish...
Save the workspace file.
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