Freud User Manual
button in the overlays panel; a new contour button will appear in the instance bar of the base window. The window associated with the popup window will appear once you click on the newly created button
The data browser is connected to the contour instantiation by using the Data menu, or by pressing control-D.
Once the data is loaded, the Source and Variable fields are filled in with the source and variable you chose from the data browser.
The fields labeled Reference, Interval, Min, and Max determine which contour values will be displayed. The first contour line is determined by the reference field. The interval value is then added to this value; if it is less than the max value, a new contour value is created. This continues while the value is greater than the max value. Similarly, the interval value is subtracted from the reference value; if it is greater than the min value, a new contour value is created. This is repeated while the calculated value is greater than the minimum value.
For example, if the Reference field has a value of 460, the Interval field 20, the Min field 450, and the Max field 600. The drawn contour values will be:
(460,480,500,520,540,560,580,600)
You can fill in contour fields by hand. or set them automatically. If you leave all of the fields blank, Freud will fill in some "nice" contour values when you press the Plot button. You can also set the values before plotting by either selecting Autoset contour values from the Edit menu, or pressing control-A.
(460,480,500)
while group 2 might contain:
(505,510,520,535)
if you wanted better resolution in the range of contours between 505 and 535.
A new group is created by pressing MENU on the Group button. Four choices are displayed:
If you wish to display the data "as-is," without interpolation, you should use the uninterpolated raster fill method.
The style, width, color, and labels of contour lines and the style, color, and fill pattern of contour areas or regions are set by means of the two scrollable lists labeled Lines and Areas at the top of the window.
When the attribute window first appears, a scrollable list of lines is displayed in the Lines list. Each line is followed by a number, followed by the letter `L' in parenthesis. The `L' indicates that the contour line will be labeled, while the number indicates the value of the particular contour line.
The line style, width, color, or label can be changed by selecting a line, and then operating on that line. A line is selected by clicking the SELECT button while the cursor is over the line. Additional lines can be selected by clicking the SELECT button on those lines. If a line is selected, it can be deselected by clicking SELECT on that line.
The SELECT menu, which is attached to the SELECT button at the top of the line or area list, gives you further control over selection.This menu allows you to select all items in the list, deselect all items in the list, select all items from the last selected item in the list to the bottom of the list, or select all items from the first selected item to the top of the list.
Selected lines can be operated on by using the menus and buttons beneath the list of lines. To change the style of selected lines, choose one of the line styles in the Style menu. All selected items in the list will be changed to that particular line style. The line width is set by using the Width menu; color is set by using the Color menu; by clicking the SELECT button over either the On or Off choices on the Label button, you can determine whether or not a given line will be labeled.
All operations on selected items are reflected in the lines list; for instance, if you change the color of a line, the list will display the new color.
If you wish to change the selected lines to the current menu and button settings, press the Apply button.
You can turn on or off the display of all contours by selecting On or Off from the Display menu.
The Areas list is controlled in a similar manner; areas are selected and then operated on. You also can set the fill of contour areas to a graded shade of colors by using the Color scale menu (see "Color scaling" on page 35).
You have a choice of several different colormaps through the colormap menu(see "Colors" on page 15).
The following label attributes can be set:
The plot was made by first instantiating a contour object, then overlaying the contour object with a map object, and finally overlaying the map object with another contour object.
Generated with CERN WebMaker
Editing contour values
First, load some data into the contour instantiation. Freud is distributed with some sample datasets; try the file `testh.cdf' in the sample directory in the Freud library directory (usually /usr/local/lib/freud/sample/testh.cdf). Contour groups
Contours can be divided into groups. A group consists of a set of contour values and properties. When the contour window of Freud is invoked, the set of contours you define are in group 1. If you wish to specify another set of (different) contour values and properties for a given source and variable, you can create a new group. For instance, group 1 could contain the set of contours:
Contour fill method
You can choose one of three different contour shading algorithms by using the Fill method choice item on the contour base window. By default, interpolated raster fills are chosen; in general, this is the fastest of the interpolated methods, and the speed of the fill is independent of the number of points in the dataset. There are two drawbacks to using this fill method--printing of plots generated in this manner are slow, and the filled areas may not exactly match drawn contour lines. Contours shaded with interpolated area fills will match drawn contour lines and may, in certain cases, be faster than raster fills. However, the time needed to generate a fill increases fairly rapidly as the number of contour lines in the plot increases.
Detailed control of contour line style, line color, area fill, and area color can be set from the Lines/Fill window (see Fig. 12). This window will appear in place of the main contour window if you select Lines/Fillfrom the contour Properties menu.
Contour Lines and Areas Color scaling
A range of contour fill colors can be set at once by using the Color Scale menu. You must first select the contour areas to be filled. If you then click on the Apply button in the menu, the fill colors for each area will be set automatically; the default for a gray colormap is for the colors to range from black to white. You can set your own stopping and starting colors by clicking on Set... in the menu. A popup window will appear. The starting color is the color of the lowest area value; the ending value is the color of the highest area value. If there are more contour areas than colors, the sequence will repeat. Intermediate areas use the colors that are displayed between the starting and ending colors on the color menu.
There are several other ways to control the contour display. These options can be accessed by selecting Labels/misc from the properties menu.
Labels and other properties
Contour line smoothing can be switch on or off from this window, and, finally, the Scale Factor field allows you to scale the values of the input data; selecting a scale factor of 10 for data that is between 0 and 100 will cause the displayed contours to be between 0 and 10. Contour example
Fig. 14
Freud User Manual - 02 FEB 96
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