Use the Contour Lines option to overlay contour lines on an image displayed in an ENVI Classic display group. For complete details on using the Contour Plot dialog, refer to the topic "Plotting Contour Lines" in the ENVI Classic Help. Here are some basic steps for overlaying contour lines on images:

  1. From the Display group menu bar, select Overlay > Contour Lines. The Input Contour Band dialog appears.
  2. Select the band from which to generate the contours. Only bands that are the same size as the displayed image are available. The Contour Plot dialog appears, listing eight default contour levels in the Defined Contour Levels area. The image's minimum and maximum data values are used to define the contour levels. The Min and Max fields show the levels.
  3. Enter the minimum and maximum values in the appropriate fields. Click Reset to return the range to its initial values.
  4. By default, ENVI plots the contours in the Image, Scroll, and Zoom windows. To plot the contours in fewer windows, clear the appropriate Window check boxes at the bottom of the dialog. The check boxes that remain selected indicate in which window to draw the contour.
  5. Click Apply to plot the contours.