Anchor Nodes

The color spectrum is defined by anchor nodes at user-defined points along a color spectrum in the Colormap Editor. Colors and opacities are automatically blended between adjacent anchors. Anchor nodes are represented by a slider button along a line on the Color Mapping and Opacity Mapping data histograms.

Anchor Node Value

The data value for the node is displayed in the Data Value box. Except for the first and last nodes, any node can be assigned to a specific value by typing a new number into the Data Value box. The first and last node data values are controlled by the Min and Max in the Data section.

Add Anchor Node

You can add additional anchor nodes at any position along the colormap. To create a new anchor node, double-click on the data histogram where you want the new node added. In the Color Mapping section, the new anchor is assigned a Color and Data Value based on where you clicked. In the Opacity Mapping section, the new anchor is assigned an Opacity and Data Value corresponding to the exact location you clicked. You can add as many anchor nodes as you want. This lets you blend colors and opacities in many different ways on the colormap.

Delete Anchor Node

Left-click on an anchor node and press the DELETE key on the keyboard to delete a node. The first (far left) and last (far right) anchor nodes cannot be deleted.

Positioning a Color Anchor Node

To position an anchor node:

  1. Move the mouse cursor over the slider button.
  2. Click and hold the left mouse button.
  3. Drag the slider button to the desired position and release the left mouse button. As you move the slider button left or right, the data value is indicated in the Data Value box. Alternatively, you can set the anchor to a specific data value by entering a number into the Data Value box. Note that the beginning and ending anchors cannot be moved or deleted.
  4. Specify the Min and Max values in the Data section to change the range, and therefore, the position of the starting and ending nodes.

Selecting a Color for an Anchor

To select a color to associate with the anchor node in the Color Mapping section:

  1. Click on the anchor you wish to modify.
  2. Click on the desired color in the Color palette. The color spectrum is updated to indicate the change.

Alternatively, use a preset .CLR color file by selecting one of the options from the Presets list or click the Load button to load a custom .CLR file.

Positioning an Opacity Anchor Node

To position an anchor node:

  1. Move the mouse cursor over the slider button.
  2. Click and hold the left mouse button.
  3. Drag the slider button to the desired position and release the left mouse button. As you move the slider button left or right, the data value is indicated in the Data Value box. Alternatively, you can set the anchor to a specific data value by entering a number into the Data Value box. As you move the slider button up or down, the Opacity value is increased or decreased. Alternatively, you can set the anchor to a specific value by typing a number in the Opacity box. Note that the beginning and ending anchors cannot be moved or deleted.
  4. Specify the Min and Max values in the Data section to change the range, and therefore, the position of the starting and ending nodes.

Select an Opacity for an Anchor

To select an opacity to associate with the anchor node in the Opacity Mapping section:

  1. Click on the anchor you wish to modify.
  2. Type the desired value in the Opacity field. The color spectrum is updated to indicate the change.

Alternatively, click and drag the anchor node up or down, use a preset .CLR color file by selecting one of the options from the Presets list, or click the Load button to load a custom .CLR file.

See Also

Colormap Editor