Draw a Line to the nearest Polygon.

akshayloya

Hi,

I've some set of points which I'm joining to make a line. Refer the Picture below.

The problem I'm facing is there are no points(elevation points) on the polygon (River Bank). Is there any way of extending the line to the polygon?

akshayloya

Refer this code instead:

 

import arcpy
import math
import os
import numpy as np
from numpy import trapz
arcpy.env.overwriteOutput = True

fc = r'D:/PTWork/GIS_RIVER/23_elevation.shp'
fld_memo = 'TxtMemo'
fc_river = r'D:/PTWork/GIS_RIVER/RB_23.shp'
fc_out = r'D:/PTWork/GIS_RIVER/RiverBank1.shp'
fld_id = 'LineID'
id_format = 'CS-{}'
tolerance = 350
dist = 100 # distance, in units of projection, to extend the line on each end

flds = ('OID@', 'SHAPE@', fld_memo)
lst_data = [[r[0], r[1], float(r[2])] for r in arcpy.da.SearchCursor(fc, flds)]

# create output featureclass
sr = arcpy.Describe(fc).spatialReference
ws, fc_name = os.path.split(fc_out)
arcpy.CreateFeatureclass_management(ws, fc_name, "POLYLINE", None, None, "ENABLED", sr)
arcpy.AddField_management(fc_out, fld_id, "TEXT", None, None, 25)

# insert cursor
flds = ('SHAPE@', fld_id)
cnt_id = 0
with arcpy.da.InsertCursor(fc_out, flds) as curs:
lst_lines = []
lst_pnts = []
for i in range(1, len(lst_data)):
print("i:{}".format(i))
lst_cur = lst_data
lst_prev = lst_data[i-1]
pntg_cur = lst_cur[1]
pntg_prev = lst_prev[1]
dist = pntg_prev.distanceTo(pntg_cur)

if dist <= tolerance:
# add to existing list
pnt = pntg_cur.firstPoint
z = lst_cur[2]
pnt.Z = z
lst_pnts.append(pnt)
else:
print(" - create and store line and add point to new list...")
# create and store line and add point to new list
if len(lst_pnts) > 1:
polyline = arcpy.Polyline(arcpy.Array(lst_pnts), sr, True, False)
lst_lines.append(polyline)
cnt_id += 1
line_id = id_format.format(cnt_id)
fc_line = arcpy.MakeFeatureLayer_management(polyline, "fc_line")
fc_poly = arcpy.MakeFeatureLayer_management(fc_river, "fc_poly")
with arcpy.da.SearchCursor(fc_poly, "SHAPE@") as scur:
for poly, in scur:
boundary = poly.boundary()
arcpy.SelectLayerByLocation_management(fc_line, "WITHIN", poly)
with arcpy.da.SearchCursor(fc_line, "SHAPE@") as ucur:
for line, in ucur:
arr, = line.getPart()
SR = line.spatialReference
p1, p2 = arr[:2]
angle = math.atan2(p2.Y - p1.Y, p2.X - p1.X)
p = arcpy.Point(p1.X - dist * math.cos(angle),
p1.Y - dist * math.sin(angle))
arr.insert(0, p)

pn1, pn = arr[-2:]
angle = math.atan2(pn.Y - pn1.Y, pn.X - pn1.X)
p = arcpy.Point(pn.X + dist * math.cos(angle),
pn.Y + dist * math.sin(angle))
arr.append(p)

line = arcpy.Polyline(arr, SR)
line = line.cut(boundary)[1]

curs.insertRow((line, line_id))
else:
# not enough points to create line
pass
pnt = pntg_cur.firstPoint
z = lst_cur[2]
pnt.Z = z
lst_pnts = [pnt]