How do I extend a Horizontal Alignment?

This question cam up today so I thought I would capture a short video on how to do this process.

The user was trying to report Points as Station, Offset, Elevation using the Station/Offset report but some of their points were long and short of the ends of the alignment.

So in order to report those points, in the current report at least you have to extend the alignment in the short and long directions by e.g 100’ so you can report the points.

The next question of course is then how do I extend an alignment?.

For the purposes of the report, unless you are reporting delta elevations to the alignment, you only need to extend the horizontal alignment in order to get Station and Offset values. It is of course risky changing or adding vertical alignment extensions because you will likely get those wrong and then will be reporting bogus Delta Elevations as a result, so I don’t recommend that.

The video below shows how to extend a HAL in both directions. I do it mechanically by using a Polyline to create the line extensions and then use the HAL editor to modify the alignment. That way you can check that you did not louse up somehow in the process. You can use the COGO snaps directly in the AL editor if you want to shortcut the creation of polylines, but you use the check that the polylines give you.