Raster Properties

General Properties | Drawing Style | Raster Sources | LUT | Image Info

The Raster Properties dialog is used to display properties of a raster display layer. It can be launched by right clicking on the desired raster layer in the Layer Manager.


Layer: view, and modify the layer name. This name is also displayed in the Layer Manager. To modify, type in a new name in it's place.

Visibility: Make this layer visible, or invisible. The same thing can be accomplished with the eye icon on the Layer Manager.

Editable: Currently this control has no effect.


Drawing Style

Modulation Color: Set the color to modulate the layer with. Selecting red, green or blue will cause the layer to only affect red, green or blue, with other RGB components showing through. An RGB composite can be created from three layers by setting each to be modulated by different component colors.

Setting the opacity of the modulation color (via the custom... entry) effectivly sets the opacity (alpha) for the whole layer. Alpha blending can also be achieved using the Alpha band of RGB layers on the Raster Sources tab.

Subpixel Interpolation: Determines whether screen values should be deduced from image values by linear interpolation, or decimation (pick one of possible pixels).


Raster Sources

The Raster Sources tab allows control of the input raster bands used to generate the display layer. Each input component can be independently scaled, band mappings can be changed, and components can be set to use fixed scales instead of source bands.

Band: Select the band to use for this component from the file for this layer. At this time it is not possible to alter the source file after creation of the raster layer. If the value constant is selected instead of a band number, the scaling min/max controls will be replaced with an entry control which can be used to enter a single fixed value to use for that component for the entire layer.

Non-eight bit data (16bit integer, and floating point) is scaled to eight bit (range 0-255) before compositing, or putting through the layer lookup table. The scale minimum is mapped to 0, and the scale maximum to 255. The default scaling values are selected based on a 2% tail trim of a histogram of 10000 sample pixels from the image. Values outside the initial min/max range may be selected by typing them into text entry control.

Scale Min: Set the minimum value for scaling to eight bit.

Scale Max: Set the maximum value for scaling to eight bit.



The LUT tab only appears for complex raster layers, and allows five options for how the 2D (real and imaginary) components of the complex data will be mapped into a color for display. The options are:

  1. Magnitude and Phase: Produce an image with HSV hue indicated by the phase, and HSV value indicated by the magnitude of the complex values.

  2. Phase: Produce an image with HSV hue indicating the phase of the complex values.

  3. Magnitude: Produce a red scale image showing the magnitude of the real and imaginary values.

  4. Real: Produce a greyscale image showing only the real component of the complex data.

  5. Imaginary: Produce a greyscale image showing only the imaginary component of the complex data.

The displayed color swatch is the 2D LUT, with the vertical axis indicating increasing real values downwards, and the horizontal axis indiating increasing imaginary values to the right.

Image Info

The Image Info tab displays additional information about the image, including any metadata stored within the file.