Draw Arc

Function Description

Draw an arc, which can be determined by parameters such as center, endpoint, start point, radius, and angle. Multiple methods can be used to create arcs (or elliptical arcs). The application provides three commonly used ways to draw arcs: circular arc, three-point arc, and elliptical arc.

Feature Entry

  • Edit Data tab -> Object Drawing group -> Line drop-down menu -> Arc.

Operation Instructions

Draw an Arc by Specifying Three Points (Three-Point Arc)

  1. When the current layer is editable, in the Edit Data tab's Object Drawing group, click the Line drop-down button, select the Triple-Point Arc option, and the three-point arc cursor appears.
  2. Move the mouse into the map, and you can see that as the mouse moves, the parameter input box behind will display the current coordinate values in real time. Enter the coordinate values of a point on the three-point arc in the parameter input box (you can switch between the two parameter input boxes by pressing the Tab key) and then press the Enter key to confirm the start position of the three-point arc.
  3. Move the mouse again, enter the coordinates of the second point in the parameter input box, and press Enter to confirm.
  4. Continue moving the mouse, enter the coordinates of the last point in the parameter input box, and press Enter to complete the drawing of the three-point arc.
  5. Right-click to cancel the current drawing operation.

Draw an Arc by Specifying Start Point, Center, and Angle (Circular Arc)
  1. In the Edit Data tab's Object Drawing group, click the Line drop-down button, select the Circular Arc option, and the circular arc cursor appears.
  2. Move the mouse into the map, and you can see that as the mouse moves, the parameter input box behind will display the coordinate values of the point in real time. Enter the coordinate values of the start point in the parameter input box (you can switch between the two parameter input boxes by pressing the Tab key), and then press the Enter key to confirm the center.
  3. Move the mouse again and enter the radius (length) of the circle in the subsequent parameter input box, then press Enter to draw a circle.
  4. With the drawn circle as a reference, move the mouse and enter the start angle in the subsequent parameter input box (the start angle is the counterclockwise angle between the positive X-axis and the starting radius of the arc) to determine the start position of the arc.
  5. After determining the start angle of the arc, continue moving the mouse, enter the swept angle of the arc in the subsequent parameter input box, and press Enter to draw an arc.

Draw an Elliptical Arc

  1. When the current layer is editable, in the Edit Data tab's Object Drawing group, click the Line drop-down button, select the Ellipse Arc command, and the elliptical arc cursor appears.
  2. Move the mouse, enter the coordinates of the start point of one semi-axis (major or minor semi-axis) of the oblique ellipse in the parameter input box (you can switch between the two parameter input boxes by pressing the Tab key), and then press Enter to confirm the start position of the semi-axis of the oblique ellipse.
  3. Move the mouse, the map will display the length of the line connecting the mouse position and the semi-axis start point and its angle with the positive X-axis in real time. Enter the length and angle values in the parameter input box (you can switch between the two parameter input boxes by pressing the Tab key), press Enter to execute the input, and complete the drawing of one semi-axis of the oblique ellipse.
  4. Continue moving the mouse, enter the length of the other semi-axis in the parameter input box, and press Enter to complete the drawing of the oblique ellipse.
  5. Move the mouse, enter the start angle in the subsequent parameter input box (the start angle is the counterclockwise angle between the positive X-axis and the starting radius of the arc) to determine the start position of the elliptical arc.
  6. Continue moving the mouse, enter the swept angle of the elliptical arc in the subsequent parameter input box, and press Enter to draw an elliptical arc.
Notes:

Arcs drawn in a line dataset are ordinary line objects, which only record the coordinates of each node on the line. However, arcs drawn in a CAD dataset are parametric objects, which record corresponding parameters, such as radius and center.