Surveys: Positioning Constraints

Positioning constraints are position/orientation/scale priors based on user tie points. They are used to perform a rigid registration of the block during aerotriangulation.

Positioning constraints are used only when using "Use positioning constraints on user tie points" mode during aerotriangulation.

You can set the origin and/or the scale and/or the orientation (either on axis or a plane).

Property	Description
Origin constraint	Add constraint type > Origin constraint. You cannot add an origin constraint if another origin constraint exists. Select the point corresponding to the Origin O=(0,0,0).
Scale constraint	Add constraint type > Scale constraint Select two points A and B and specify the distance between them. Select the distance unit if you know it, or use "units (arbitrary)" if it is not defined. You can add several scale constraints.

Property

Description

Origin constraint

Add constraint type > Origin constraint.

You cannot add an origin constraint if another origin constraint exists. Select the point corresponding to the Origin O=(0,0,0).

Scale constraint

Add constraint type > Scale constraint

Select two points A and B and specify the distance between them.

Select the distance unit if you know it, or use "units (arbitrary)" if it is not defined.

You can add several scale constraints.

Axis constraint

Add constraint type > Axis constraint Orientation constraint based on an axis.

Select two points A and B and an axis, line AB being this axis (increasing values from A to B).

You cannot add an axis constraint if another orientation constraint exists (axis or plane constraint).

Plane constraint

Add constraint type > Plane constraint Orientation

Constraint based on a plane

Select three points and two axes to specify a plane.

You cannot add a plane constraint if another orientation constraint exists (axis or plane constraint).