Colour Legend Bar

When designing a map that includes a grid, you may want to add a colour legend bar based on the grid. You can do this quickly using the functionality available through the Colour Legend Bar tool (geogxnet.dll(Geosoft.GX.Map.ColourBar;Run)*) and create a horizontal or vertical legend bar for a colour grid or a colour-shaded grid image.

You can view your changes without closing the dialog. By keeping the dialog open and modifying the colour bar settings, you’ll notice that the changes are dynamically applied to the map’s colour bar.

The tool can be accessed from the following locations:

  • The Grid and Image > Display on Map menu
  • The Map Tools > Symbols menu
  • The Section Tools menu
  • The Euler 3D > Plot Solution Symbols menu with the Grav/Mag Interpretation extension

Colour Legend Bar dialog options

Data layer

Select the data layer to use to generate the colour legend bar. The colour zones in the legend bar will be based on the selected AGG group/data layer.

To add a colour legend bar, a map must include a view\AGG_layer for the primary colour bar ITR.

Script Parameter: COLORBAR.AGG

Second data layer

Optionally, select a second colour layer, generally intended for adding shading to the colour bar for a shaded-colour image. The secondary colour scheme is blended horizontally within, to the primary colour scheme.

To plot only the primary colour scheme of a shaded colour grid, leave this entry blank.

Script Parameter: COLORBAR.AGG2

Titles

Title

Specify the colour bar title (generally referring to the grid it represents).

Script Parameter: COLORBAR.TITLE

Sub-title 1 & 2

Up to two additional lines can be used to further elaborate, for example, on the data colour distribution (e.g., linear distribution) or on defining the data units.

Script Parameters: COLORBAR.SUBTITLE & COLORBAR.SUBTITLE2

Title location

Specify the location of the title relative to the colour bar.

If the Orientation selection is Vertical, the title location can be:

  • Above

  • Below

If the Orientation selection is Horizontal, the title location can be:

  • Above, centered

  • Above, left justified

  • Below, centered

  • Below, left justified

Script Parameter: COLORBAR.TITLELOC [ |0 - Below Left |1- Below & Below centered |6 - Above left |7 - Above & Above centered]

Title text size (mm)

Specify the size in millimetres for the title text.

Script Parameter: COLORBAR.TITLE_SIZE

Sub-title text size (mm)

Specify the size in millimetres for the sub-title text.

Script Parameter: COLORBAR.SUBTITLE_SIZE

Colour Bar

Orientation

The colour bar can be displayed vertically or horizontally to best suit the map layout. Select one of the two options below:

  • Vertical

  • Horizontal

Script Parameter: COLORBAR.BAR_ORIENTATION [0 – Vertical |1 – Horizontal]
Location

X & Y Location (mm)

 

Specify the location of the lower left corner of the colour bar from the lower left corner of the map, in plotting units (millimetres).

Script Parameters: COLORBAR.X & COLORBAR.Y

[Locate]

Click the Locate button to interactively select the desired colour bar location; the selected point is the lower left corner of the colour legend bar. The X & Y Location values are updated based on the selected location from the lower left corner of the map.

If the map already contains one or more colour legend bars for other grids (AGGs), you are prompted to select a new location or you can use the same location as one of the existing legend bars.
Size

Width /Height (mm)

Specify the smallest dimension of the colour bar. Depending on the bar orientation, this parameter will refer to either the width or the height of the bar:

  • If the Orientation selection is Vertical, this parameter refers to the Width of the bar.

  • If the Orientation selection is Horizontal, this parameter refers to the Height of the bar.

Script Parameter: COLORBAR.WIDTH

Height style

You have the option to specify a fixed size for either the colour legend bar or for the colour subdivisions in the bar:

  • Fixed – select this option to specify a fixed height for the vertical bar or a fixed width for the horizontal bar. The dimension of the colour bar subdivisions (cells) will then be calculated based on the fixed bar size and the number of colour bins (i.e., the number of colour zones associated with the selected Data layer colour scheme).

  • Auto /Variable – select this option if you want to specify the size of the colour bar cells. The vertical bar height or the horizontal bar width will then be determined based on the specified cell size and the number of colour bins (i.e., the number of colour zones associated with the selected Data layer colour scheme).

Script Parameter: COLORBAR.HEIGHT_STYLE [ 1 - Fixed |0 - Auto/Variable]

Height /Width (mm)

Or

Cell height /Cell width (mm)

If the Height style option is Fixed:

  • If the Orientation selection is Vertical, this parameter refers to the Height of the bar.

  • If the Orientation selection is Horizontal, this parameter refers to the Width of the bar.

Enter the bar height /bar width (in millimetres).

Script Parameter: COLORBAR.MAXHEIGHT

If the Height style option is Auto /Variable:

  • If the Orientation selection is Vertical, this parameter refers to the Cell height of the bar.

  • If the Orientation selection is Horizontal, this parameter refers to the Cell width of the bar.

Enter the cell height /cell width (in millimetres).

Script Parameter: COLORBAR.HEIGHT

Labels

Labels

You can be post the annotations using either grid values or percentile breaks:

  • Values (default)

  • Percentiles (the "%" sign will be added to the colour bar annotations on the map.)

Script Parameter: COLORBAR.POST [ 0 - Values |1 - Percentiles]

Label intervals

You can annotate the colour legend at:  

  • Colour break (default): annotations are at the boundaries between colours.
  • Custom intervals: annotations are at equal-data intervals.
  • Specific intervals: annotations are based on user-defined intervals.
If the annotations are too close (i.e., they overlap), they will be suppressed. You may need to increase the size of the bar or decrease the label size. In addition, for custom intervals, first the fine-interval annotations are dropped, followed by the coarse-interval annotations, as required.

Script Parameter: COLORBAR.ANNO_LOCATION [0 - at colour break| 1 - custom intervals| 2 - exact intervals]

Custom intervals

 

If this option is selected, the contextual entries Coarse and Fine become available.

You must specify the coarse interval; however, the fine interval is optional and allows for further gradation of the colour bar annotation.

The drop-down list of the Fine interval is restricted to 1/2, 1/4, 1/5, and 1/10 of the Coarse interval value.

The grid summary statistics (minimum, maximum, mean value, standard deviation) are displayed to assist you with choosing the two intervals:

Script Parameters:

COLORBAR.FIXED_INTERVAL

COLORBAR.FIXED_MINOR_INTERVAL

Specific intervals

If this option is selected, you will be prompted for an Interval filename – this is the file containing the interval (bin) values. The values in the file should be either comma separated on one line or one value per line.

If the number of bins (in the colour table) does not match the number of supplied colour levels (intervals), or if all intervals are above or beyond the colour zone, an informative tooltip message is displayed. Check the minimum /maximum values of the interval file against the minimum /maximum values of the grid to make sure the two ranges overlap.

You can set the specific intervals to be further apart in the low (or high) values at the expense of seeing more detail (smaller intervals) in the high (or low) values.

Script Parameter: COLORBAR.EXACTINTERVAL_FILE

Post end value /Post end percentile

You can post the data minimum and maximum end values or the colour stretch limits, and you can also opt for no labels at the two ends of the colour bar:

  • Data: the minimum and maximum of the (grid) data range are posted.

  • Colour scheme: the minimum and maximum values of the colour distribution are posted.

  • None: no labels are added at the two ends of the bar.

You can adjust these values to cover a smaller range or to round them off. Use the calculator button located next to the fields to restore the default values.

The end values of the colour bar on the map will be annotated with the same number of significant digits and with the same size as the rest of the annotations.

Script Parameter: COLORBAR.POST_END_VALUE [ 0 - None |1 - Data| 2 - Colour scheme]

Minimum value /Maximum value

 

If post by Values is selected, these entries are populated with the minimum and maximum values of the data range or colour distribution.

Script Parameters:

COLORBAR.MINIMUM_END_VALUE

COLORBAR.MAXIMUM_END_VALUE

Minimum percentile /Maximum percentile

If post by Percentiles is selected, the entries will default to a first and last value of 0 and 100 respectively.

Script Parameters:

COLORBAR.MINIMUM_END_VALUE

COLORBAR.MAXIMUM_END_VALUE

Add ≤ or ≥ symbol to last values

You may want to turn on this option, for example, when your data exceeds the colour stretch limits; this will add a prefix to the last label of the end values to symbolize the "less than, equal to" and "greater than, equal to" values.

Script Parameter:

COLORBAR.ADD_GREATER_LESS_THAN_SYMBOLS [ 0 - No |1 - Yes]

Division style

The colour scheme can be optionally subdivided by separators. The separator can be:

  • a solid line (default) 

  • a tick

  • none

Script Parameter: COLORBAR.DIVISION [ 0 - None |1 - Solid | 2 - Tick]

Text size (mm)

Specify the label text size in millimetres.

For the Custom intervals selection:

  • If only a Coarse interval is defined: the labels will be annotated with the specified text size and a font weight of “Medium”.

  • If a Coarse interval and a Fine interval are defined:

    • The coarse-interval labels will be annotated with the specified text size and a font weight of “Bold”.

    • The fine-interval labels will be annotated at 75% of the specified text size and a font weight of “Medium”.

Script Parameter: COLORBAR.ANNSIZE

Number of decimals

Specify the number of decimals for the annotated values.

Script Parameter: COLORBAR.DECIMALS

Orientation

The labels are annotated horizontally by default. When plotting a horizontal colour bar, the use of vertical annotations may be preferable for better clarity. Select your option:

  • Vertical

  • Horizontal

Script Parameter: COLORBAR.LABEL_ORIENTATION [0 - Horizontal | 1 - Vertical]

Placement

The annotation can be placed: 

  • to the left or to the right of a vertical bar.

  • above or below a horizontal bar.

Script Parameter: COLORBAR.ANNOTATION_SIDE [0 - left/above |1 - right/below]

Minimum gap between labels (mm)

Specify the distance between annotations. By default, annotations that "overprint" will be dropped. If the default gap is not satisfactory, then provide this parameter.

If the maximum height is set, and the product of the colour cell height and the number of zones exceeds the maximum height, this value will be reduced to avoid "overprinting".

Script Parameter: COLORBAR.MINIMUM_GAP

[Apply]

Click the Apply button to create the colour legend bar on the map or to apply the current settings to an existing colour bar. For a new legend bar, a group is created in the Base view as "COLORBAR _view name_AGG group_grid name".

The dialog remains open, and you can view your changes applied interactively on the map.

*The GX.NET tools are embedded in the geogxnet.dll file located in the "...\Geosoft\Desktop Applications \bin" folder. If running this GX interactively, bypassing the menu, first change the folder to point to the "bin" directory, then supply the GX.NET tool in the specified format. See the topic Run GX for more details on running a GX.NET interactively.