The currently selected data layer (AGG_, voxel) file or symbol group (CSYMB_) is listed.

The tool enables you to interactively modify the colour grid zones. The following transform methods for zoning data are available:

• Linear: the range of data values are divided linearly into even increments.
• Normal distribution: your data is assumed to be normally distributed and the zones are determined based on the standard distribution for a standard bell curve.
• Histogram equalization: your data layer values are evaluated and the zones are statistically determined, such that data is equally divided among the histogram bins. The equal-area is the default zoning method.
• Log-Linear: the zone values are updated based on the log distribution of the data, and the data is displayed using the log-linear transform.
• Custom: this is not a selectable item; it is a contextual read-only item that appears if you are using a user-defined distribution. See the description of the user mode button () below.

Click on the Define Distribution button located to the right of the Distribution field* to open the associated transform dialog: define the colour values or keep the intelligent defaults and click OK to close the transform dialog.

The Define Distribution button becomes disabled when the 'Custom' user-defined distribution is selected.

The initial state of the brightness is set at 50% (full colour). Slide the bar to adjust the brightness: 0% generates the darkest possible image, while 100% generates the brightest possible image.

If the data layer is composed of many layers, you can interactively apply the desired brightness:

• On all layers: select the All button.
• To the current layer only: keep the Current button default selection.

The initial state of the transparency is set at 0% (opaque image). To increase the transparency, slide the bar to the right.

If the map contains image and vector (i.e., survey path and/or symbols) layers, decreasing the transparency of the image makes the vector layers stand out better.

Enter a number for the colour breaks (zones). By default, the number of bins is set to the number of colour zones in the colour table. If you enter a different number, the colour table is linearly interpolated/decimated to the provided number of bins while maintaining the colour distribution. For example, if the colour table has 255 levels but the number of zones is set to 15, then only the colours of rows 0,17,34,51, etc., will be used.

Bins Colours & Boundary Values

The bins colours and boundary values are displayed in a scrollable window.

To turn off a given bin on the image display, simply uncheck its Active*  checkbox. This will be indicated on the Transform graph with a hashed grey pattern (see the Application Notes below).

To toggle multiple adjacent bins:

1. Move the mouse to the first bin then click on the left mouse button.
2. While holding down the Shift key, select the last bin.
3. Finally, simultaneously click on the Shift key and the left mouse button.

The colour distribution of the selected layer is loaded in the Colour field. To change the colour for a specific bin:

1. Click on the colour box to invoke the Colour dialog.
2. Select/define a new colour, then close the dialog to apply the change.

To change any of the colour breaks, simply enter new values in the respective Minimum and Maximum fields*. The adjacent boundary values will be automatically updated.

Transform Window

The Transform window displays the binned data distribution of the current data layer/symbol group using the selected colour zoning method.

The grey profile traces the number of points within each bin at a finer resolution.

The black profile corresponds to the cumulative number of points as a percentile and is annotated along the right vertical axis.

When the cursor is inside the transform graph, a set of normal dashed lines indicate the range of the zone at the cursor location (see the Application Notes below).

The colour bar, located below the horizontal axis of the graph, is annotated with the absolute values of the bin boundaries.

Hover your mouse pointer over the colour bar until a tooltip appears: the name of the current colour scheme will be displayed.

In order to visually enhance features of interest, a number of interactive options are provided to scroll through, zoom in, and modify the number, colour and size of bins.

Zoom in/out the Transform window

Use the arrows at each end along the top of the window to change the graph’s horizontal extents:

• A click on the left or right arrow will move the end value of the graph to the boundary value of the next bin.
• Click on the "reset" arrows to restore the graph to its full extents.

Extend a colour bin*

You can modify the size of individual colour bins to accentuate specific subtle features; the adjacent bins will adjust accordingly:

• On the colour bar located along the bottom of the transform graph, position the cursor over a bin separator until the separator is highlighted and the cursor changes to a 2-way crosshair cursor: 
• Click and hold down the left mouse button and drag it to the desired position.
• Release the left mouse button to complete the operation. The colour image will be updated.

Shift a colour bin*

You can shift the colour of a bin to a different bin; the number of bins (colours) on either side of the moved colour bin are maintained, and the bin boundary values on either side are resized/readjusted to keep the same number of bins and all the colours:r

• On the colour bar, position the cursor inside a colour bin until the boundary annotations of the colour bin are highlighted.
  The cursor will change to a 4-way white arrow:
• Left click and hold the mouse button, then move it to the bin you would like to assign this colour to.
• Release the left mouse button on the intended bin.

The difference between this feature and the circular scroll is that colours assigned to the end bins won’t change. However, if the bin is moved too far to one side to the point that the bin sizes become too small (i.e., smaller than the smallest interval), the colour of the bin whose width is too small is dropped and bin boundary values are redistributed.

If the image contains a large number of bins, it can become difficult to place the cursor inside a bin, versus on the boundary of the bin. To reach the desired outcome, press and hold the Ctrl key; the cursor changes to a 4-way white arrow indicating that you are in "scroll" mode. Place the cursor over the desired bin to move, left click, and move the colour of the bin to the new location.

The information icon on the top left of the graph contains a tooltip reminder*; hover your mouse pointer over the icon to see the tooltip.

Custom colour distribution*

The standard methods are based on a Gaussian data distribution. This is, however, not always the case; you may want to customize the colour distribution to put more emphasis on a data range of interest at the expense of regions of little relevance:

• To activate the custom mode, click on the button.
• When you are satisfied with the colour distribution, click on the button to save it.
• To abandon the custom mode, click on the button.

See the Application Notes below for further details.

Leave this option unchecked when the data distribution is Gaussian by nature. The Logarithmic axis option should be used when the data distribution spans over many orders of magnitude, and a sizable amount of the data resides towards the low values of the data distribution scale. The use of a logarithmic scale will help emphasize the low values on the transform graph and highlight more detail.

Click this button to flip the colours around. The changes are automatically applied to the active document (i.e., map, grid, 3D view, voxel) and in the transform window (the graph and the transform line are redrawn).

When working interactively with grids or coloured 3D symbols and voxels, you often experiment in order to determine the optimal colour combination for your data. Click the Reset button ( ) to restore the colour distribution to the initial input settings (i.e. the last version stored in your data file or symbol group).

When experimenting with various colour distributions, it is recommended that you save them to unique colour scheme files. After modifying the colour distribution, you can save the new colour distribution along with the binning breaks to a file. You can then reset the colour distribution, experiment with another colour combination, and save this combination to another file.

Click on the Save button to save the current colour distribution/bin values to one of the file formats (*.ITR, *.AGG, *.ZON, *.TBL and *.LUT) available in the file selection dialog. The file filter is set to "Colour zones (*.zon)" and the file name (editable) defaults to "data layer/symbol group.zon".

You can later use this file to display grids or symbols with the colour breaks occurring at the values indicated in the selected colour table file.

When you want to compare or apply a previous colour distribution, simply load the corresponding colour scheme file. Click this button to open the Select Colour Scheme tool and select from a variety of predefined colour schemes in several categories and formats. Click [OK] to load the selected colour scheme (e.g., zone file, colour table).

Hover the mouse over the colour bar located below the histogram graph: a tooltip will appear displaying the current colour scheme file.

Press the button to close the Colour Tool dialog and apply the changes made to the active document (i.e., map, grid, 3D view, voxel).