Feature

Feature Description

In editable state, update part of line or polygon objects with drawn polylines. The Local Update function can form new objects using the intersecting parts between the drawn polyline and source object (the line object to be updated).

• The Local Update function applies to line layers, polygon layers, and CAD layers.
• When no target object is selected, the start and end points of drawn polylines must be on the target object's boundary. It is recommended to enable snapping during operation.
• When target objects are selected, Clip Mode can be used for updating. The drawn polyline must have at least two intersection points with the target object.
• Objects participating in Local Update can be simple objects or individual sub-objects of complex objects, but not compounds.
• In Local Update operations, results vary depending on the object type. Details for updating line and polygon objects are explained below:
  • Updating unselected line objects (Snapping Mode)

    The following diagram shows Local Update operation on an unselected open line object.

    Figure 1 shows the line object to be updated. Using the polyline drawn in Figure 2 for updating (both start and end points must be on the line), the highlighted bold segment in Figure 2 represents the Local Update result.

    The update polyline divides the target object into three segments. After confirming the polyline's start/end points, press Ctrl or Shift to toggle Local Update results, as shown by the highlighted bold segment in Figure 3.

    Figure 1: Object to be updated	Figure 2: Local Update operation	Figure 3: Toggling Local Update result

  • Updating selected line objects (Clip Mode)

    The following diagram shows Local Update operation on a selected open line object.

    Figure 4 shows the line object to be updated. Using the polyline drawn in Figure 5 (requiring ≥2 intersection points), the highlighted bold segment represents the Local Update result.

    The update polyline divides the target object into three segments. After confirming the polyline's start/end points, press Ctrl or Shift to toggle results, as shown in Figure 6.

    Figure 4: Object to be updated	Figure 5: Local Update operation	Figure 6: Toggling Local Update result

  • Updating unselected polygon objects (Snapping Mode)

    The following diagram shows Local Update operation on an unselected closed polygon.

    When the polyline's start/end points are confirmed on the polygon boundary, the preview shows blue area as update result (Figure 8), with updated boundary highlighted. Press Ctrl/Shift to toggle results, shown as blue area between highlighted segments in Figure 9.

    Figure 7: Closed polygon to be updated	Figure 8: Local Update result 1	Figure 9: Local Update result 2

  • Updating selected objects (Clip Mode)

    The following diagram shows Local Update operation on selected closed polygons.

    The polyline's start/end points can be inside or outside the polygon boundary, but must have ≥2 intersection points. The preview shows blue area as result (Figure 11) with updated boundary highlighted. Press Ctrl/Shift to toggle results, shown in Figure 12.

    Figure 10: Closed polygon to be updated	Figure 11: Local Update result 1	Figure 12: Local Update result 2

Feature Entry

• Features Tab->Feature Editing Group Dropdown->Local Update.

Steps

1. Set layer to editable state in Layer Manager.
2. Click Local Update in Features Tab's Feature Editing Group Gallery. The map cursor changes to polyline mode .
3. Two operation modes available:
   • Snapping Mode: Move cursor to target object's boundary. Start/end points must be on boundary. If not, output window prompts: "The point should be on the line when updating with Snapping Mode. Please select an object if you want to update with Clip Mode." Requires redrawing start point.
     Note:

     Enable Point Snapping to Lines in Snapping Settings before using Snapping Mode.

   • Clip Mode: Select target object first. The polyline can start inside/outside boundary but must have ≥2 intersection points.
4. Continue drawing polyline. When points snap to target object, updated shape highlights automatically. The polyline divides object boundary into segments. Hold Ctrl to toggle boundary selection.
5. Right-click to confirm update with current shape, completing Local Update operation.