Retrospective Formatting

Changing Plot Axes

Limits

The axes limits in x, y, z or colour can be changed by the commands lx, ly, lz and lc respectively. Colour limits define the lowest and highest values to which colours are allocated. Anything below the lower limit will be the lowest colour and any points above the upper limit will be the highest colour.

>> lx(xlo, xhi)
>> ly(ylo, yhi)
>> lz(zlo, zhi)
>> lc(clo, chi)

• If the selected plot is an area plot then lz and lc both change the colour scale
• lz and lc are not applicable for one dimensional plots
• If no limits are given to a command the following happens:
  • lx - x limits are between the lowest and highest value of x in the data
  • ly - y limits are between the lowest and highest value of y in the data contained within the current x limits
  • lz/lc - z/c limits are between the lowest and highest value of z in the data contained within the current x and y limits

Changing the Scale to Log

The axes scale for x, y, z and colour can be changed to a logarithmic scale using the commands logx, logy, logz and logc respectively.

>> logx
>> logy
>> logz
>> logc

• If the selected plto is an area plot then logz and logc both change the colour scale
• logz and logc are not applicable for one dimensional plots
• If the scale is already logarithmic then nothing happens (i.e. no warning or error is given)

Similarly, the axes scale for x, y, z and colour can be changed to a linear scale using the commands linx, liny, linz and linc respectively.

>> linx
>> liny
>> linz
>> linc

• If the selected plto is an area plot then linz and linc both change the colour scale
• linz and linc are not applicable for one dimensional plots and will simply do nothing
• If the scale is already linear then nothing happens (i.e. no warning or error is given)

Changing the Aspect Ratio

>> aspect(x_ulen, y_ulen, z_ulen)

• Aspect ratio is changed so that x_ulen in the x axis, y_ulen in the y axis and z_ulen in the z axis have the same length on screen
• z_ulen is optional, if not given and applicable then the z axis retains its height (not its aspect ratio)

Alternaltively instead of changing the aspect ratio for the current axes, one can give the function an axes handle or the name and tag of the plot to change.

>> aspect('name', 'tag', x_ulen, y_ulen, z_ulen)
>> aspect(axesHandle, x_ulen, y_ulen, z_ulen)

• Only plots with the given name and tag or axesHandle will be altered

One can also let Matlab decide the appropriate aspect ratio to fill the figure by typing

>> aspect(axesHandle, 'auto')
>> aspect('name', 'tag', 'auto')

Adding a Legend

To add a legend to a one dimensional plot, use the command

>> set_legend('string1', 'string2', ...)

• Adds a legend to the current plot
• Strings should be in the reverse order to the order that lines were plotted

EXAMPLE:

>> dl(w1,'color','red')
>> pm(w2, 'color','blue')
>> pm(w3, 'color','green')
>> set_legend('marker plot of w3', 'marker plot of w2',...
'line plot of w1')

• Red line will be labeled 'line plot of w1', blue markers will be labeled 'marker plot of w2', green markers will be labelled 'marker plot of w3'

Finding Points on a Plot

Finding and labelling points on a plot is done using the dxyz command. This can also place text on the plot at the desired point. A set of crosshairs will appear on the currently selected figure. By clicking on a point the x, y and z coordinates are found and returned through the function, any text is placed at the point.

>> dxyz
>> dxyz('text')
>> [x, y] = dxyz
>> [x, y, z] = dxyz
>> [x, y, z] = dxyz('text')
>> [x, y, z] = dxyz('property', value)
>> [x, y, z] = dxyz('text', 'propterty', value)

where 'property' and value relate to property-value pairs which are given below.

• By default, points will be returned until the return key is pressed on the keyboard
• If no output arguments are requested then the co-ordinates of the points are added as text at the point selected
• If text is given it is added to the plot (before the co-ordinates if they are to be added)
• If the plot is one dimensional then the returned z value will always be 0
• Function can be called without the z output
• If on a surface, the point chosen will be the (x,y,z) coordinate of the first face of the surface which intersects the selection ray (which is a "ray that goes into the screen). If no face intersects then NaN is returned.
• If on an area plot then the z value will be the intensity value of the pixel that was selected
• If on a [[Plot Commands#Two Dimensional Plots|multiplot] or one dimensional plot then the returned values will be the x,y,z points that corresponds to the closest data point on the closest intersecting face to the selection ray.

Optional Properties

Property	Possible Value	Behaviour	Default
'text'	Any string value	Text is added to the selected point	BLANK
'no_points'	Any numeric value	Defines the number of points that are to be selected on the plot. Once 'no_points' number of points have been sleected, the function will end. If left blank, this has the same as the default behaviour	Infinate
'display_coords'	True or False	If true, then the co-ordinates of the points selected will be placed on teh graph at the slected points. If text is given as well, the co-ordinates will be appended to the end of the text	False
'closest_point'	True or False	The co-ordinates of the closest actual point of the data is returned as the point	False

EXAMPLE:

>> [x,y,z] = dxyz('label')<pre>


The user will see 

[[image:dxyzparta.jpg|300px|user selects a point]]


<pre>user clicks on point
user presses return

label is placed at the point

user rotates the view

rotated view