The Relief theme styles Grid items; it assigns different colours to different Grid values.

When the Grid is a Digital Terrain Model (DTM), the colours can represent ranges of heights.

Click Home > Add Theme > Style and select Relief.

Click Next to open the Coloursets dialog.

The Relief theme can be used on a DTM:

  1. If not yet selected, the Theme Overlay dialog allows you to select the overlay containing the DTM.
  2. Click Next to display the Theme Types dialog.
  3. Select Relief and click Next.
  4. The Coloursets dialog will be displayed. Choose an appropriate colourset to indicate the heights.
  5. Click open the Relief Styles dialog.

Option Description


The units to display in the theme legend.


The number of decimal places to display in the theme legend.

Show units in legend

Check this tickbox if you wish to include the chosen units in the theme legend.

Compact Legend

Check the Compact Legend tickbox to show the legend in compact form. (See below for examples).


This drop-down box is active when the Vertical radio button is selected. This is a sizing factor for the vertical display. The range of numbers available depends on the number of values in the theme.

Labels - Horizontal/Vertical

The Labels setting controls whether the labels are displayed alongside the legend. The Horizontal/Vertical setting controls the orientation of the legend.


This pane shows the colours that are defined in the colourset. The colours are shown as pairs in a colour-value range.

Coour- Hue

The wavelength of the colour. This corresponds to a position in a rainbow of colours. (range 0-240)


The purity of the colour. For example, pink is an unsaturated form of red. Primary colours are saturated, pastel colours are unsaturated.(range 0-240)


The brightness of the colour. Very dim colours become black. (range 0-240)


The degree of transparency, 0 being fully opaque and 255 being fully transparent. (range 0-255)

No data colour

Coloursets store a 'nodata' colour. This allows reordering of the HLS (Hue, Lightness, Saturation) controls into the more commonly used HSL (Hue, Saturation and Luminosity) order and enables the New value - Add button when viewing a read-only Colour-set.

Blend colours

Check this tickbox if you wish to blend and smooth colours for values that fall between colour-value pairs. Choosing this option leads to smooth transitions between colours.


This option allows colour-value pairs to be added to the colour-value list. Enter the value to be added in the text box and click Add.

For example in a list of colour-values:





adding a value of 150 would result in new colour-value pairs being added to the list:



Deletes a selected colour-value pair. Select the colour-value pair for deletion and click Delete. The lower range value will automatically change to include the deleted range.


Spread: This option combines both the Spread colours and Spread transparency functions.

Spread colours

Where you have three or more colour-value pairs, you can let SIS use graduated colours through the range. Selecting a colour for the first colour-value pair and another colour for the last colour-value pair. Highlight all the values for which you want the colour graduated and click Spread colours.

Spread transparency: This option will spread graduated levels of transparency across the range of selected colour-value pairs.

Compact Legend

Note: Check the Compact Legend tickbox; check or uncheck the Labels tickbox. Select the Horizontal or Vertical radio buttons- the display can be with or without the values being shown and in vertical or horizontal orientation.

Compact Legend tickbox checked

As it will appear in the Maps Control Bar:


Compact Legend tickbox unchecked

As it will appear in the Maps Control Bar:

Filter, Scale and Legend buttons

Note: Click here for Relief Theme properties.