Surface or solid with colour banding

The name of the layer that contains the data to colour. The active layer is the default value. You can draw data from all layers in Graphics by leaving this field blank.

The string or triobject range to draw in Graphics. The range must be a standard range specifier. You can leave this field blank to draw all objects in the active layer.

The segment or trisolation range to draw in Graphics. The range must be a standard range specifier. You can leave this field blank to draw all trisolations of each object you are drawing.

The triangle range to draw in Graphics. The range must be a standard range specifier. You can leave this field blank to draw all triangles in each trisolation you are drawing.

The triangle range can be useful when your are trying to diagnose problems in creating 3DMs, for example, when you want to see if you have unintentionally created duplicate triangles.

The name of the field, in the string file, to use for interpolating the colours across the triangle faces. Valid entries include; X, Y, Z, and description fields. You only need to define the field to colour by if you are using the bands of specified size, set number of bands or range for bands colouring options.

These options determine how the trisolations will be drawn. The meanings of the banding types are shown in the following table.

Triangle colouring is performed by drawing colour bands of a specified thickness where the top and bottom of each colour band is exactly on a contour value . The contour value is determined by Field to colour by and Size of bands.

When you select this option, the Size of bandsfield is displayed,. This value is the thickness of each band of colour. For example, when you are colouring on the Z field with four colours (blue, green, yellow, and red) and Size of bands is 5, the first 5 units of elevation are coloured blue, the next 5 are coloured green, and so on. After 20 units of elevation, the colour sequence is repeated.

Note:

• Any triangles, or parts of triangles, that are smaller in value than the smallest value in the range entered, are coloured using the first colour. Any triangles, or parts of triangles, that are greater in value than the highest value in the range entered, are coloured using the last colour.
• The results, using colouring by range, are only approximate. Inaccuracy in the colouring can occur when there are no triangle vertices at the locations where the colours must change and when the widths of the colour bands varies. You can overcome this shortcoming by extracting contours at levels of interest, creating a DTM of the contours and then applying the colour range to the DTM of the contour strings.

Triangle colouring is performed by using algebraic expressions to determine when to use the specified colours. You define a list of colours and the expression associated with each colour. If the expression results in a value of zero, the colour is not used. If the value is not zero, the triangle is drawn in the colour, and no further expressions in the list are considered for that triangle. Expressions are processed in the order they appear in the list, so that the triangle is drawn in the colour of the first expression that results in a non-zero value.

The expression can use the following variables.

Note: The variable names are not case sensitive.

D1, D2, D3, ..., D100

These variables refer to the values stored in the description fields of the triangle. See the CLASSIFY DTM TRIANGLES function to see how values can be assigned to the triangle description fields.

AVGD1, AVGD2, AVGD3, ..., AVGD100

These variables refer to the arithmetic mean of the values from the description fields of the three points used for the vertices of the triangle. The values in the point description fields must be numeric for this to be successful. These variables effectively refer to the value of the point description fields at the triangle centroid position. Processing will stop with an error message if a non-numeric value is encountered.

X, Y, Z

These variables refer to the triangle centroid X, Y or Z value.

DIP

This variable refers to the maximum dip, expressed in decimal degrees, of the triangle. Values are always positive and range between 0 and 90 degrees in value.

DIPDIR

This variable refers to the direction of the maximum dip, expressed in decimal degrees. DIPDIR has a value >= 0 and < 360. The direction always points in the downhill direction of the maximum dip.