About Contour Maps

This topic provides you with terms and concepts you should understand when creating contour maps in Terrain Preparation.

See Also
Creating Contour Maps

You may select a terrain that can be a mesh or a surface, specify contour map options, and Terrain Preparation creates contour maps.

Creating contour maps involves determining the contour interval by specifying major and minor lines. This option is sufficient in most cases. If you want to generate a specific contour map (for example corresponding to a lake or river), you can use the supplementary option. Prior to generating the contour map envisioned, it is necessary to select options in the Contour Map dialog box. The key parameters are shown and described below:

A contour map is defined by the:

  • Range comprising the upper and lower altitude.
  • Major plane step that is the steps between two lines.
  • Number of minor lines between two major plane steps.

Optionally:

  • Origin: If the terrain origin does not correspond to the sea level, you must select a point representing the sea level.
  • First plane altitude: In most cases, the altitudes of major planes are the multiples of the major plane step, and the default zero value corresponds to this situation. If this is not the case, you can specify another value for it.

The Contour Map command generates:

  • Contour lines
  • Terrain characteristic points such as terrain peaks, saddles, depressions, as well as grid points between two contour lines.
    Note: You can show or hide the contour lines and points, together or independently.

Example: A terrain whose lowest altitude value is 1534.75m and highest altitude value is 2467.6m.

Consider the above example. To create the contour map, you must specify the following values:

  • The step between two major planes
  • The number of minor contour lines between two major planes
  • The range (lower altitude and upper altitude) within which contour lines need to be generated

The Lower altitude value must be greater than or equal to the terrain lowest Z value. The Upper altitude value must be less than or equal to the terrain highest Z value. If the default value for First plane altitude is 1600m, the major lines will be generated successively at 1600m, 1700m, 1800m altitudes. These are multiples of the step between two major planes ( step = 100m). If you want to generate major lines at 1650m and 1750m altitudes you must enter 1650m as First plane altitude.

You can project contour maps in 2D drawings.

Warning: Contour map values can be shown in the 2D view only when the XY plane is selected as the reference plane.