Creating Lines Perpendicular to Linear Features

Hi,

 

 

You can use the offsetter on a second stream of features to achieve that.

 

Optionally the offsetcurvegenerator can also be of use.

Not sure how that would work.  My intention is to look at say a 100 foot long line go along that line from the starting point 13 feet and then create a line perpendicular to the original line and 20 feet long to the left side of the original line then say go 25 feet along the original line from the starting point and create a line perpendicular to the original and 20 foot long to the right. The 20 foot long lines tee into the 100 foot long lines at designated distances from the starting point. Does this make sense?

Hi Jim,

 

 

For simplifying the explanation, assume that the original line is a line segment having only 2 nodes  (start (x0, y0) and end (x1, y1)) and its length is 100 ft..

 

  1) Calculate the unit vector (ux, uy) of the original line segment. ux = (x1 - x0) / 100 uy = (y1 - y0) / 100   2) Create the left-side perpendicular line of 25 ft., move its starting point to the 13 ft. location along the original line from (x0, y0): Rotate the original line around (x0, y0) by 90 degree. Snip the beginning 25ft. of the rotated line. Offset the snipped line by (ux * 13, uy * 13).   3) Create the right-side perpendicular line of 20 ft., move its starting point to the 25 ft. location along the original line from (x0, y0): Rotate the original line around (x0, y0) by 270 degree. Snip the beginning 20 ft. of the rotated line. Offset the snipped line by (ux * 25, uy * 25).

 

 

Result:

 

To do this, consider using the CoordinateExtractor, LengthCalculator, ExpressionEvaluator (or AttributeCreator), Rotator, Snipper and Offsetter etc.. In addition, be aware that the result of division becomes an integer value if both of denominator and numerator are integer values. Use "@double" function to cast at least one operand of / operator to prevent it.

 

 

Takashi

P.S. as Itay suggested, you can also use the OffsetCurveGenerator, instead of unit vector calculation and the Offsetter.

hi

 

 

like takashi and itay suggests make use of the

 

1. curveoffsetter at the appropriate distance, then

 

2. create points along the original line by using the distancemarker (make sure that each points has got a unique id or numeric value, consider using a counter etc)

 

3. use the neighbourfinder between points along the line vs offseted line,

 

4. now all points will have a base and candidate XY, split the flow inot two parts, base XY and candidate XY - and create pair of points per unique id

 

5. connect paired points by pointconnector

 

6. snipp or shorten each created perpendicular line to the exact length u need

 

 

now it should be solved..

 

 

regards

 

 

andre

 

 

Dear old subject :)

 

Last year I published a transformer named 2DVectorCalculator in FME Store. In fact, the idea was born from this discussion.

 

First, snip the starting part of the given length from the source line with the Snipper. Then, use the 2DVectorCalculator to create the required perpendicular line from the remnant part.

 

Start Index: 0

 

End Index: 1

 

Vector Direction: Normal Left (or Normal Right)

 

Vector Length: <required length of the resulting perpendicular line>

 

Replace Geometry: Yes