For example, the following code displays an image contained in the variable A and then draws a contour plot of pixels [ Symbols can be of any size and can have up to 50 vertices. For all other routines, the default is to enable clipping. Other keywords you can explore include: This keyword indicates the line style used to draw lines; it indicates the line style of the lines used to connect the data points. Note Since T3D uses the transformation matrix in! The axis line, major tick marks, and minor tick marks are omitted.

The maximum axis value is automatically set by IDL from the maximum y data value. See Fonts for a complete description of IDL’s font systems. The plot in the upper right has outward-facing tick marks. Not all devices support erasing the background to a specified color index. For example, to transfer three 8-bit images contained in the arrays R, G, and B to their respective channels, use the following statements:. The program is as follows:. The value for the [xyz]style keyword is a bitmap and that values can be added together to set more than one property.

Frequently, when data points are ;lot against the results of a fit or model, symbols are used to mark the data points while the model is plotted using a line.

See Specifying the Location of the Plot for more information. Other bits in the STYLE field extend the axes by providing a margin around the data, suppress the axis and its notation, and suppress the box-style axes by drawing only left and bottom axes. Shift down to the first level subscript and decrease the character size by a factor of 0. The clipping itself always occurs in device space. The first parameter is the radius, and the second is the angle expressed in radians.

Graphics Keywords

For lpot, if you would like to suppress the x axis: MULTI equal to an integer vector in which: Polar plots are produced using the standard axis and label styles, with box axes enclosing the plot area. The display is erased if this field is zero when a new plot is begun. The figure below illustrates this, fitting the Sockeye population values to a quadratic function of the year.


If X is not specified, Y is plotted as a function of point number starting at zero.

IDL sets the plot window to produce the given number of plots on each page and moves the window to a new sector at the beginning of each plot. Example of Logarithmic Scaling. Y axis only Noticed that the values are not in sequencial order. Display the X axis tick values using a format of F6.

The plot region is the box enclosing the plot-data window and the titles and tick annotation. The default coordinate system is DATA if no other coordinate-system specifications are present. First, we define a procedure called BOX, which draws a box given the coordinates of two diagonal corners:. No data points are plotted. If the X argument is present, the X axis is positioned accordingly, and setting XAXIS equal to 0 or 1 causes the tick marks to point up or down, respectively.

If you do this, IDL scales the axis from the first tick value to the last unless you directly specify a range. The current position is set from the top of the saved position stack. Force x range to [0, 1], ; centering xval, which also contains the tick values.

To plot symbols instead of lines you should xstgle PSYM. For example, a value of -5 plots triangles at each data point and connects the points with lines. When specifying an x-axis, the x-coordinate parameter is plto, but must be present if there is a y coordinate.

Coordinates are expressed in normalized units ranging from 0. If set to zero, the default, IDL automatically determines the number of minor ticks in each major tick-mark interval.

Using AXIS for polar plots.

4. Visualization

This can be achieved in several ways:. TV, B, 0, 0, 3. Two factors cause this effect.

A text string to be used as a subtitle for the plot. Array elements 80 through are set to 1: Setting this field equal to 1 suppresses tick marks. Xtsyle following plotting routines allow you to set maximum and minimum values in this manner: The default clipping rectangle is the plot window, the area enclosed within the axes of the most recent plot.


It is convenient to use NSUM when there is an extremely large number of data points to plot because it plots fewer points, the graph is less cluttered, and it is quicker. Polygons is the name of the variable with the list of polygons to be created. The tick marks ; point left: MULTI 0is set to zero to cause the next plot to begin a new page. These keywords correspond to fields in the axis system variables: Controlling Tick Marks and Their Annotation.

A string array of up to 30 elements that controls the annotation of each tick mark. There is a procedure, xloadctthat would ploot you to interactively load and display the available color table in IDL.

Beginner’s IDL – Line Plots

The figure below illustrates the data plotted using this keyword. Set bit 4 in! For example, to transfer three 8-bit images contained in the arrays R, G, and B to their respective channels, use the following statements:.

Plot with Xstyel Range of to Figure This keyword controls the thickness of the lines forming the xyor z axes and their tick marks. You must allow space for the annotation, which resides outside the window, otherwise an error message will warn you. To plot your symbol you need to set PSYM to plus or minus 8.

When specifying a keyword parameter name and value in a call that value affects only the current call, the corresponding system-variable field is not changed. Set this keyword to produce polar plots. Fanning which has been installed in our local libraries directory. Use a callback function to display the Y tick values as a percentage of a fixed value.