How to Reverse a Line in Arcgis Pro?
Reversing a line in ArcGIS Pro is typically done using the Reverse Line editing tool, which changes the digitized direction of a selected line feature.
Steps to Reverse a Line in ArcGIS Pro
The primary method for reversing a line's direction in ArcGIS Pro involves using the built-in editing tools. Follow these steps:
- Start an Edit Session: Ensure you have a feature layer in your map that you can edit and that editing is enabled for that layer.
- Select the Line(s): Use the Select tool from the Map tab to select the polyline features you wish to reverse.
- Open the Modify Features Pane: Go to the Edit tab on the ribbon. In the Features group, click the Modify button. This opens the Modify Features pane.
- Find the Reverse Line Tool: In the Modify Features pane, expand the Reshape tools or use the search bar to find the Reverse Line tool. Click on the Reverse Line tool.
- Apply the Reversal:
- If you selected the lines beforehand, the tool might automatically list them or show options to apply to selected features.
- Alternatively, with the Reverse Line tool active, you can click on the specific line features you want to reverse in the map view.
- Save Edits: After reversing the line(s), go back to the Edit tab and click Save in the Manage Edits group to make the changes permanent.
Using the Reverse Line tool flips the line so that its original start point becomes the end point, and the original end point becomes the start point. This affects the direction the line is drawn and can impact how certain tools or analyses that depend on line direction (like flow direction) function.
Understanding the Impact of Reversing Lines
Reversing a line's direction can have different effects depending on the line type and its attributes:
- Standard Lines: For most simple polyline features, reversing changes the internal order of vertices and flips the start and end points. This is important for applications that use direction, such as linear referencing (M-values are measured from the start point) or network analysis.
- COGO Enabled Lines: If your selected polyline feature is COGO enabled (representing cadastral boundaries with specific direction and distance information) and the Direction field contains an attribute value, reversing the line updates this attribute accordingly. As per the reference, it is reversed by adding 180 degrees to the value. This ensures the COGO direction attribute remains consistent with the line's new digitized direction.
Important Considerations
- Attributes: Reversing a line does not typically change other attributes unless they are explicitly linked to direction (like the COGO direction field).
- Measure (M) Values: If your lines have M-values, they are usually measured from the start point. Reversing the line will flip the M-measurement direction. The original M=0 point will become the new end point, and the original M=max point will become the new start point (M=0).
- Z Values: Z-values associated with vertices remain with their respective points, but their order along the line is reversed.
Reversing lines is a fundamental editing operation used for data cleanup, correcting digitization errors, or preparing data for directional analysis.
