Function Description

In the Gallery control of the Feature Editing group on the Edit Data tab, the function to generate a fillet is provided, which extends or trims the adjacent endpoints of two line segments and connects them with an arc tangent to both lines to form a rounded corner.

• The Fillet button is only available when two line segments are selected in an editable layer, meaning this function is only effective for the selected two line segments.
• The objects involved in generating a fillet must be simple line objects, and their extended lines have one and only one intersection point. If the two lines are parallel or on the same straight line, the operation will not be successful.
• After the operation is completed, the source lines may be extended or trimmed, but the attributes will not change.
• Although fillet operations can be performed on intersecting lines, it has no obvious geographical significance, so this case will not be described in detail.

Function Access

• Edit Data tab -> Feature Editing group -> Line editing -> Endpoint editing -> Fillet

Operation Instructions

1. Set the object layer of the line segments for fillet generation as the current editable layer.
2. In the layer, simultaneously select two line segment objects (non-parallel lines).
3. In the Line editing drop-down menu on the Edit Data tab, click the Fillet button in the Endpoint editing group to pop up the Fillet Settings dialog box. The default fillet radius is one-fifth of the maximum inscribed circle radius of the two line segments. The unit of the fillet radius is consistent with the unit of the current editable layer.
4. Set the arc radius, i.e., the radius of the arc tangent to both lines. The result of generating the fillet will determine the position and size of the fillet based on the user-set arc radius, thereby appropriately extending or trimming the two line segments involved in the operation. As the arc radius is modified, the preview will real-time display the fillet operation result, facilitating user adjustment.
5. Set whether to trim the source object. Checking this item means that after the operation is performed, the source object will be trimmed; otherwise, the original object will be retained.
6. In the map, the preview effect of generating the fillet will be displayed in real time. Click the OK button to execute the fillet generation operation based on the user's settings, and the result is as shown in the figure below.

   Figure: Fillet Result

7. Operation result description: The system calculates an inscribed circle with the input radius from the selected two line segments, and finds the tangent points on each line segment to the inscribed circle. If the tangent point is on the line segment, it will be cut off; if it is on the extension line, the endpoint of the line segment will be extended to the tangent point. Then, take the outer arc between the two tangent points in the inscribed circle to generate a new line object. Its attribute record is added to the end of the attribute table, system fields: assigned by the system, non-system fields: empty values, and the original line objects retain their original attributes. The operation result is illustrated as follows:

   Figure: Schematic Diagram of Operation Process and Result