Draw Arc

Function Description

An arc can be drawn by specifying parameters such as the center, endpoints, start point, radius, and angle. Various methods are available to create arcs (or elliptical arcs). The application provides three common ways to draw arcs: Circular Arc, Triple-Point Arc, and Elliptical Arc.

Function Entry

  • Features tab -> Objects group -> Line drop-down list -> Arc.

Operation Instructions

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

  1. When the current layer is editable, in the Objects group of the Features tab, click the Line drop-down button and select the Triple-Point Arc option. The triple-point arc cursor appears.
  2. Move the cursor to the map. As the mouse moves, the parameter box following it will display the current coordinate values in real-time. In this parameter box, enter the coordinates of a point on the triple-point arc (you can switch between the two parameter input boxes by pressing the Tab key) and then press Enter to determine the starting position of the triple-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 final point in the parameter input box, and press Enter to complete drawing the triple-point arc.
  5. Right-click to cancel the current drawing operation.

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

Draw an Elliptical Arc

  1. When the current layer is editable, in the Objects group of the Features tab, click the Line drop-down button and select the Ellipse Arc command. The elliptical arc cursor appears.
  2. Move the mouse, enter the starting point coordinates of one semi-axis (major or minor) 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 determine the starting position of the oblique ellipse semi-axis.
  3. Move the mouse. The map will display in real-time the length of the line connecting the mouse position and the semi-axis starting point, as well as its angle with the positive X-axis direction. In the parameter input box, enter the length and angle values (you can switch between the two parameter input boxes by pressing the Tab key) and press Enter to execute the input, completing the drawing of one semi-axis of the oblique ellipse.
  4. Continue moving the mouse, type 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 following parameter input box (the start angle is the counterclockwise angle between the positive X-axis direction and the starting radius of the arc) to determine the starting position of the elliptical arc.
  6. Continue moving the mouse, enter the angle swept by the elliptical arc in the following parameter input box, and press Enter to draw an elliptical arc segment.
Note:

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