Upon completion of this chapter the student will be able to:
• Define the following terms: point, line, bearing, foreshortened line, oblique line, inclined line, bearing, azimuth, locus, longitude and latitude.
• Determine the equivalent distance in statute miles and feet for a given degree of latitude.
• Determine the equivalent in hours of a given degree of longitude.
• Use the AutoCAD commands list, id, and properties to determine the location of a point.
• Describe the difference between a bearing and an azimuth.
• Determine the bearing and azimuth of a given line.
• Convert from bearings to azimuths and from azimuths to bearings.
• Use AutoCAD to determine the bearing and azimuth of a line.

All objects, whether they are man-made or the result of natural conditions and/or forces, contain points and lines.
They are the basic building blocks for all two- and three-dimensional objects.
Both points and lines have been widely studied in almost every technical field.

• This grid network provides worldwide coverage and consists of a system of meridians and parallels known as lines of longitude and latitude.
• Meridians are lines of longitude that run north-south;
• The meridian passing through Greenwich, England, is 0 ° longitude or the prime meridian.
• Measurements can be made east or west of the prime meridian and range from 0 ° to 180°.
• Lines of longitude west of the prime meridian are designated by the letter
W, or prefaced with a negative ( –) sign.

• Longitude and latitude are measured in degrees, minutes, seconds (DMS).
• Each degree is made up of 60 minutes, and each minute contains 60 seconds.

• Angles will vary from 0° to 90°.
• Require a reference plane at the beginning and end.
• Are measured from either a clockwise or counter clockwise direction.
The bearing in the above figure is N60°E

• Angles will vary from 0° - 360°.
• Require only a numeric value, they are assumed to be referenced from due north unless otherwise specified.
• Are measured only in the clockwise direction.

Using North as a Reference
• For all lines in the first quadrant the angle associated with the bearing will be the same for the azimuth.
• For all lines in the second quadrant the azimuth is calculated by subtracting the bearing from 360 °.
• For all lines in the third quadrant the azimuth is calculated by adding the bearing to 180 °.
• For all lines in the fourth quadrant the azimuth is calculated by subtracting the bearing from 180 °.

Using South as a Reference
• For all lines in the first quadrant the azimuth is calculated by adding the bearing to 180 °.
• For all lines in the second quadrant the azimuth is calculated by subtracting the bearing from 180 °.
• For all lines in the third quadrant the angle associated with the bearing will be the same for the azimuth.
• For all lines in the fourth quadrant the azimuth is calculated by subtracting the bearing from 360 °.

• Is the percentage of inclination between a line and the horizontal plane. It is defined as the vertical rise of a line divided by its horizontal run with the quotient multiplied by 100