TANGENT INTERSECTION LABELING

[jonyreb]

How do you add a left or right label to an existing tangent label. we are adding an offset entry to our tangent intersection label. it either gives us ??? or removes the LT or RT from the deflection angle and gives us both LT and RT in the offset entry. Our label should read as follows:

Str No
Sta
Deflection angle and direction LT or RT
Offset = xx' LT or RT

[tpadgett]

Only way I have found is to Edit Label Text and add manually.

[GTVic]

You can create a label for both and use an expressions for the text height. The expression should give a very small text height if that label doesn't apply.

Expression that returns 1 if it is a left turn, zero if right turn based on isLeft function from here: (http://stackoverflow.com/questions/1560492/how-to-tell-whether-a-point-is-to-the-right-or-left-side-of-a-line). Followed by expressions that supply a text size.



Expression: Left Turn
IF(((({PI Easting} - {Spiral 1 Start Easting}) * ({Spiral 2 End Northing} - {Spiral 1 Start Northing}) - ({PI Northing} - {Spiral 1 Start Northing}) * ({Spiral 2 End Easting} - {Spiral 1 Start Easting})) > 0),1,0)
Expression: LT Label Size
IF ( {Left Turn} = 0 , 0.00001 , 0.04 )
Expression: RT Label Size
IF ( {Left Turn} = 1 , 0.00001 , 0.04 )

This is code given by Autodesk that does something similar but I'm not sure it works in all cases.

if
({Tangent In Direction}> pi,
if
({Tangent Out Direction} < {Tangent In Direction}
&
{Tangent Out Direction} > if ({Tangent In Direction}< pi, {Tangent In Direction} + pi, {Tangent In Direction} - pi),
0.004,
0.00001
)
,
if
(
({Tangent Out Direction}<{Tangent In Direction}
&
{Tangent Out Direction}>=0
)
|
({Tangent Out Direction}< 2*pi
&
{Tangent Out Direction} > if ({Tangent In Direction}< pi, {Tangent In Direction} + pi, {Tangent In Direction} - pi)
),
0.004,
0.00001
)
)