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Creating a Transect from a Surface





A transect is a profile of the intersections created by the transect object (a line, arc, spiral or traverse) and the triangles (TIN) generated by the surface.   Transects are helpful in site analysis and design.

When you create a transect, you add the computed intersections to a new or existing traverse. Once added, the traverse can be viewed as a profile, showing the transect of the surface.

You’ll find all the instructions for creating a transect in the Transect command.

Transects with Lines and Arcs

When you transect a line or arc, TPC computes the intersection of the line or arc with the triangle edges in the TIN. A point is inserted into the transect traverse for each intersection.

Transect Dialog

When you transect a drawn object, like a line or arc, the Transect dialog asks you to select the traverse to place the transect in. You can select an existing traverse, in which case TPC will append the transect to that traverse, or you can enter the name of a new traverse.

You can also specify a starting point label for the new transect points that will be computed.

Transects with Traverses

When you select a traverse as the transect object, things work a little differently. Instead of computing the intersections of the traverse and the triangles, TPC computes the elevation of each traverse point that lies within the surface and places a copy in the transect traverse and updates the elevation of the copy to match the elevation of the surface at that point. You end up with a transect traverse that profiles the traverse based on the surface.

Transect Dialog

When you create a transect from a traverse, the Transect dialog has a couple of restrictions.

1.You must specify a new traverse. TPC will create a duplicate of the traverse you are transecting and place the elevations of the duplicate points on the surface. The original traverse is unchanged.

2.You will not be allowed to edit any of the label options. TPC will use the point labels in the transected traverse to create duplicate point labels in the new traverse that holds the results. This allows you to relate the new point on the surface with the original point in the transect traverse.

3.Once the new traverse is created, you can always us the Relabel tools to change it's point labels.

Transecting an Existing Traverse

When you transect an existing traverse, TPC updates the elevations of each traverse point so that each traverse point is on the surface.  See Surface Transects.

Sorting a Transect

TPC attempts to sort the transect points to that they all go in one direction. However, depending on the configuration of the surface, it may not get every point right.

You can manually re-sort traverse points if needed.

To View the Transect

Double click the transect traverse in the Traverses Manager to open its Traverse View.

Right click any blank spot on the Drawing View and choose Profile Mode. You may also need to choose View | Zoom | Zoom Extents to see the transect.

For more information on editing and using breaklines, see Creating Transects from Contours.

Related Topics

Transect command






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