Creating Points at Tangent Intersections

TPC uses the term Tangent intersections for intersections that are constrained to be tangent to an arc.

Given a curved survey line, TPC can determine where a line (originating from another point or tangent intersect) is tangent to that curved survey line.


Tangent-Tangent IntersectTake a look at the sample tangent instersection to the right.

We computed two tangent intersects,

For this example, TPC computed tangent intersects at both ends of the red tangent line.

Here is the dialog used to compute this tangent-tangent intersect example.

Tangent Intersect Dialog

Tangent - Tangent Intersection

A Tangent-Tangent intersection, like the example shown here, computes intersections so that a line passing through them is tangent to both arcs.

Tangent - Point Intersection

A Tangent-Point intersection, computes intersections so that a line passing through them and the point is tangent to the arc.

Using the Tangent Intersection Dialog

The Intersection dialog box will display the appopriate number of intersections based on the data you give it. When TPC finds a valid intersection, one or both Computed Intersection fields will be available for entry (white rather than gray).

Note: Computed Intersection fields will not be available if TPC can't find a valid intersection based on the data you entered.

Naming Intersections

TPC names the computed intersections INT1L, INT1R, INT2L, INT2R. You can rename them as needed.

The 1L, 1R, 2L and 2R indicate the location and direction of the intersections as seen from Point 1 looking to Point 2. 

So INT1R would be the tangent intersect for Point 1 as seen from Point 1 to Point 2.  INT2R would be the tangent intersect for Point 2 as seen from Point 1 to Point 2.

Viewing the Computed Intersections

Reporting the Comptued Intersections

Grid vs Ground / Geodetic

Intersections are computed based on the distance and direction types selected in the dialog.


Premium, Professional

Related Topics

Tangent-Tangent Intersections
Tangent-Point Intersections
Creatomg Points at Intersections
Using COGO
COGO Commands