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Direction and angular units

Editing tools that specify direction allow you to type direction values in polar, azimuth, or quadrant bearing units. The default direction is specific to your locale and angular units are set to degrees. You can change and save these settings for each project.

The following sections explain the direction and angular unit settings that are available in the project Options dialog box.

For steps to change direction and unit settings, see Configure unit settings for editing.

Note:

When ground to grid correction is turned on, an offset angle is applied to directions, and a distance factor multiplies distances. This occurs in real time as you create geometry using construction tools and type bearing and distance values.

To learn more, see Turn ground to grid corrections on or off.

Polar

Polar angles are measured counterclockwise from the positive x-axis starting at zero. Angular values increase in the counterclockwise direction and decrease in the clockwise direction.

This is the default setting.

Polar angles

North azimuth

In the north azimuth system, the azimuth of a line is the horizontal angle measured from a meridian to the line, measured in the clockwise direction from north.

North azimuth

South azimuth

In the south azimuth system, the angles are measured clockwise from south.

South azimuth

Quadrant bearing

The quadrant bearing system divides the compass into four equal sections of 90 degrees. The bearing of a line is measured as an angle from the reference meridian, either the north or the south, and toward the east or the west.

Quadrant bearing

Quadrant bearings are written as a meridian, an angle, and a direction. For example, a bearing of N 25 W defines an angle 25 degrees west measured from north. A bearing of S 18 E defines an angle 18 degrees east measured from the south.

The following formats are valid inputs:

  • [N or S] dd.dddd [E or W], where dd.dddd is typed as decimal degrees.
  • [N or S] dd-mm-ss [E or W], where dd-mm-ss is typed as whole degrees, minutes, and seconds with hyphen separators.
    Note:

    This format requires angular units to be set to degrees/minute/seconds.

  • dd.dddd-[1 or 2 or 3 or 4], where dd.dddd is typed as decimal degrees followed by a hyphen (-) and one of the following numeric codes:
    • 1 = NE
    • 2 = SE
    • 3 = SW
    • 4 = NW

Angular units

You can change the default angular units to any of the formats in the following sections.

Degrees

Degrees are the standard unit of angular measurement, where one degree represents 1/360 of a circle and fractions of a degree are represented as decimal values.

This is the default setting.

Degrees, minutes, and seconds (DMS)

Degrees/minutes/seconds also uses the degree, but fractions of a degree are represented in minutes and seconds, where one minute equals 1/60 of a degree and one second equals 1/60 of a minute.

The following formats are valid inputs:

  • dd-mm-ss.ss
  • dd.mmssss
  • dd^mm'ss.ss"

Radians

Radians are the International System of Units (SI) unit of plane angular measure. There are 2pi, approximately 6.28318, radians in a circle. One radian is equivalent to approximately 57.296 degrees. The length of a circular arc with an angle of one radian is equal to the radius of the arc.

Gradians

Gradians are a unit of angular measure where the right angle is divided into 100 parts. One gradian equals 1/400 of a circle.

Gons

Gons are the same as gradians. One gon equals 1/400 of a circle. The term gon is primarily used in German, Swedish, and other northern European languages where the word grad means degree.