Autotek autocad raster design 2010 Benutzerhandbuch

Data Interpretation

Select the type of data to display about the surface:

■

Height (Feet). Land elevation in feet

■

Height (Meters). Land elevation in meters

■

Value. Land elevation in other units, or other data in the file

■

Slope (Percent). Ground slope expressed as a percentage

■

Slope (Angle). Ground slope expressed as an angle

■

Aspect. Direction of ground slope

Value Distribution

This setting controls how the colors in the Range Table are distributed across
the range of data values: Parametric or Custom.

NOTE A parametric distribution automatically adapts to the range of values in
the file being displayed; a custom distribution uses fixed data values, regardless
of the range of values in the file. This difference is important if you want to save
the color map and use it on multiple data files.

If you want Raster Design to automatically set the ranges, choose Parametric,
then one of these three options:

■

Each color represents an equal range of values, regardless of how many
actual data points occupy that range for a given source file.

■

Six ranges are created, and the spread of each one is set to the standard
deviation for the data. The upper limit of the third range is the arithmetic
mean value. If the data has a normal distribution, the third and fourth
ranges embrace about 68% of the data values; the second through fifth
ranges embrace about 95% of the values.

■

Each range represents an equal number of data points in the source file.
Where readings are clustered around a narrow range of values, colors in
that range have a small range spread; where readings are sparse, the range
spread is large.

346 | Appendix B   Raster Design Dialog Boxes