Creating lines that connect to other lines

To ensure that new lines meet at existing lines, you can use snapping to help you properly place the endpoints. For example, when tracing a stream network, the ends of smaller streams should connect to a river. When mapping a transportation network, street features should connect to each other unless they are dead ends or culs-de-sac. To ensure that new lines do not have dangles, you can use the snapping environment to help you properly place the endpoints.

The task below describes how to create new lines that snap together. However, if you already have some line features that you want to connect, there are several options:

• To extend or trim a line to meet another line, use the Extend or Trim tools on the Advanced Editing toolbar.
• To move a line manually so it snaps, select a line, hold down CTRL and move its selection anchor to the end of the line, and move the line so the selection anchor (and therefore, the feature) snaps to the proper features.
• If you want to align features along the edge of one layer to features of an adjoining layer, use the edge snap spatial adjustment method.
• Try the Trim Line, Extend Line, or Snap geoprocessing tools in the Editing toolbox (requires ArcGIS for Desktop Standard or ArcGIS for Desktop Advanced).
• You can use the Integrate geoprocessing tool to make lines or vertices coincident. However, you need to be careful that you enter the smallest cluster tolerance possible so you don't inappropriately collapse or merge features.

Steps:

1. Ensure end snapping is enabled. If it is not, click End Snapping on the Snapping toolbar.
2. Ensure edge snapping is enabled. If it is not, click Edge Snapping on the Snapping toolbar.
3. Click a line feature template in the Create Features window.
4. Click the Straight Segment construction method on the Editor toolbar.
5. Snap to an existing line, then click to add a start vertex in the new line.
6. If you want the end vertex to meet at an existing line, make sure your end vertex snaps when you add the vertex and finish the sketch.
Once your features are created, using an ArcGIS for Desktop Standard or ArcGIS for Desktop Advanced license, you can use geodatabase topology to identify and fix any remaining dangles. Apply the Must Not Have Dangles rule to the line feature class, then identify and fix any errors. If a dangle error is a valid case (such as a cul-de-sac), you can mark it as an exception.