Create parallel lines within polygon

Question

How do I create parallel lines to the end of the polygon and then clip them with arcpy?

With the script I'm currently using, the lines are not created correctly.

The script I am using is this

import arcpy, math

offset = 3
offset_original = offset
features=[]


arcpy.env.overwriteOutput = True


infc="linha"
talhao = "poligono"

#arcpy.Intersect_analysis([infc, talhao], "AB_Intersect", "ALL", "", "INPUT")

spatialRef = arcpy.Describe(infc).spatialReference

def CopyParallel(plyP,sLength):
    part=plyP.getPart(0)
    lArray=arcpy.Array();rArray=arcpy.Array()
    for ptX in part:
        dL=plyP.measureOnLine(ptX)
        ptX0=plyP.positionAlongLine (dL-0.01).firstPoint
        ptX1=plyP.positionAlongLine (dL+0.01).firstPoint
        dX=float(ptX1.X)-float(ptX0.X)
        dY=float(ptX1.Y)-float(ptX0.Y)
        lenV=math.hypot(dX,dY)
        sX=(-dY*sLength/lenV);sY=dX*sLength/lenV
        leftP=arcpy.Point(ptX.X+sX,ptX.Y+sY)
        lArray.add(leftP)
        rightP=arcpy.Point(ptX.X-sX, ptX.Y-sY)
        rArray.add(rightP)
    array = arcpy.Array([lArray])
    section=arcpy.Polyline(array, spatialRef)
    return section


with arcpy.da.UpdateCursor(infc,["SHAPE@"]) as cursor:
    for shp in cursor:
        i=0
        while i <= 200:
            if (i == 0):
                twoLines=CopyParallel(shp[0],offset)
            else:
                twoLines=CopyParallel(features[-1],offset)
            features.append(twoLines)
            i=i+1

arcpy.CopyFeatures_management(features, "teste")  

Error

Answer 1

If this:

IS truly what you are trying to achieve, use cleaned up script below.

NOTE

• I have no room for 200 parallel lines, make change to the code accordingly
• this is a good idea when borrowing someone else script to make an efforts to understand it’s logic.
• If the script is not working a) explode your lines to single parts, b) repair geometries and c)read notes to this post again.

SCRIPT:

import arcpy, math
offset = 3
arcpy.env.overwriteOutput = True
infc="linha"
spatialRef = arcpy.Describe(infc).spatialReference
def CopyParallel(plyP,sLength):
    part=plyP.getPart(0)
    lArray=arcpy.Array();rArray=arcpy.Array()
    for ptX in part:
        dL=plyP.measureOnLine(ptX)
        ptX0=plyP.positionAlongLine (dL-0.01).firstPoint
        ptX1=plyP.positionAlongLine (dL+0.01).firstPoint
        dX=float(ptX1.X)-float(ptX0.X)
        dY=float(ptX1.Y)-float(ptX0.Y)
        lenV=math.hypot(dX,dY)
        sX=(-dY*sLength/lenV);sY=dX*sLength/lenV
        leftP=arcpy.Point(ptX.X+sX,ptX.Y+sY)
        lArray.add(leftP)
    section=arcpy.Polyline(lArray, spatialRef)
    return section

curT = arcpy.da.InsertCursor("teste","Shape@")
with arcpy.da.SearchCursor(infc,["SHAPE@"]) as cursor:
  for shp in cursor:
    i=0
    while i <= 3:
      if (i == 0):previous=CopyParallel(shp[0],offset)
      else: previous=CopyParallel(previous,offset)
      curT.insertRow((previous,))
      i+=1