# About creating a line with the Traverse window

This topic applies to ArcEditor and ArcInfo only.

One common COGO editing task is to create a line or polygon edge using a set of survey measurements collected in the field. The data may be in the form of directions and distances, angles and distances, curves, or tangent curves measured from a known point. These are collectively known as a traverse.

Traverse lets you create edit sketch geometry from a variety of traverse measurements. Once you've started a traverse, you can add segments or curves to the edit sketch using Direction–Distance, Angle–Distance, Curve, and Tangent Curve methods. The Traverse command adds each segment as a line in the Traverse course table and to the edit sketch. You can select each course segment by clicking it in the table—the corresponding segment will flash on the map.

## Populating COGO attributes

You can create features using the Traverse window to populate COGO attributes in a feature class and save each course in the traverse as a COGO two-point line feature.

The features must be either straight lines or circular arcs. They typically have two vertices, but more are allowed as long as each feature is consistently straight or consistently curved. In addition, the line feature class must have the following COGO attributes as text fields: Direction, Distance, Delta, Radius, Tangent, ArcLength, and Side.

By default, features are created as two-point lines when the feature class contains COGO attributes. Traverse creates individual line features for each course and automatically assigns the appropriate COGO attribute values.

## Direction-Distance course

You need to have an edit sketch with at least one vertex. You can also use the Interactive Start Point tool to set a start point for the course. You enter a direction and a distance. A new straight segment is added to the edit sketch. The direction is based on the current direction type and direction units for the editing environment. The distance can be in any of the supported distance units.

## Angle-Distance course

You must have at least one segment in the edit sketch, either from a previous course or already existing in the edit sketch. You enter an angle and a distance. A new straight segment is added to the edit sketch. The angle is based on the current direction units. The distance can be in any of the supported distance units.

The angle—also called the backsight angle—is a clockwise angle between the last segment and the intended line. To add a line tangent to the last segment, you need to use an angle of 180 degrees.

## Curve course

You need to have an edit sketch with at least one vertex. You can also use the Interactive Start Point tool to set a start point for the course. You enter two curve parameters, a curve direction, and whether the curve is to the left or right. A new circular arc segment is added to the edit sketch. A curve can be created by entering two of the following parameters:

- Chord—Also referred to as the chord distance, the straight line distance between the endpoints of the curve.
- Angle—The angle formed between the endpoints of the curve and the center point.
- Arc—Length along the curve. The arc length needs to be greater than the chord distance.
- Radius—Length from the center point to the curve.

You cannot add the tangent distance (the distance between the endpoints of the curve and their intersection point) as a parameter for the curve. If you have a tangent distance, use the Curve Calculator dialog box to determine one of the other curve parameters.

The curve direction can be one of three types:

- Chord direction—Direction from the start point of the curve to the endpoint of the curve.
- Tangent direction—Direction to the tangent point of the curve. This creates a curve where the center point of the curve is at 90 degrees from the tangent direction, on the same side as the turn direction.
- Radial direction—Direction toward the center point of the curve.

The curve direction is based on the current direction type and direction units. The angle is based on the current direction units. The distances can be in any of the supported distance units.

## Tangent curve course

You must have at least one segment in the edit sketch, either from a previous course or already existing in the edit sketch. You enter two curve parameters and whether the curve is to the left or right. A new circular arc segment is added to the edit sketch. The curve is created from the last point in the edit sketch with the center point of the curve 90 degrees from the edit sketch, on the same side as the turn direction.