Connecting Discontinuous Line Segments

DanielWalters

I have a shape file with a series of line segments that are discontinuous, I want to join them together so they form a continuous line based on a common attribute from the attribute table. I already understand how to merge the lines using Merge in the editing tool bar, but I'm not clear on if there is a way to get those segments to link up as shown in the image below (I have the broken lines on top, I want the continuous line below) without manually snapping them together point by point, as it is a large file with numerous such segments. Is there a tool in ArcGIS that can do this? Thanks.  (Note: I've seen some other postings mention the Dissolve tool, but I don't see how it applies here).

 

XanderBakker

Hi Daniel Walters‌,

I saw your question and thought, let's give it a try...

Based on this input:

Is creates this output:

Using this code:

import math

def main():
    import arcpy

    fc_in = r"D:\Xander\GeoNet\Nueva carpeta\test.gdb\lines"
    fc_out = r"D:\Xander\GeoNet\Nueva carpeta\test.gdb\lines_out"
    tolerance = 150 # max distance to snap to a node

    # create dicts
    dct_lines = getPolylineDict(fc_in)
    dct_from, dct_to = getFromAndToNodes(dct_lines)

    # loop through polylines
    for oid, polyline in dct_lines.items():
        # search candidates from point
        pnt_from = dct_from[oid]
        dist_min = tolerance + 0.01
        pnt_found = None
        for oid_from, pnt in dct_from.items():
            if oid_from != oid:
                dist = calcDistance(pnt_from, pnt)
                if dist < dist_min:
                    dist_min = dist
                    pnt_found = arcpy.Point(pnt.X, pnt.Y)

        for oid_to, pnt in dct_to.items():
            if oid_to != oid:
                dist = calcDistance(pnt_from, pnt)
                if dist < dist_min:
                    dist_min = dist
                    pnt_found = arcpy.Point(pnt.X, pnt.Y)

        # change line from point
        if pnt_found != None:
            polyline = insertPointAtStart(polyline, pnt_found)
            dct_lines[oid] = polyline
            dct_from, dct_to = getFromAndToNodes(dct_lines)

        # search candidates to points
        pnt_to = dct_to[oid]
        dist_min = tolerance + 0.01
        pnt_found = None
        for oid_from, pnt in dct_from.items():
            if oid_from != oid:
                dist = calcDistance(pnt_to, pnt)
                if dist < dist_min:
                    dist_min = dist
                    pnt_found = arcpy.Point(pnt.X, pnt.Y)

        for oid_to, pnt in dct_to.items():
            if oid_to != oid:
                dist = calcDistance(pnt_to, pnt)
                if dist < dist_min:
                    dist_min = dist
                    pnt_found = arcpy.Point(pnt.X, pnt.Y)

        # change line end point
        if pnt_found != None:
            polyline = addPointAtEnd(polyline, pnt_found)
            dct_lines[oid] = polyline
            dct_from, dct_to = getFromAndToNodes(dct_lines)

    # create list of polylines
    lst_polylines = dct_lines.values()
    arcpy.CopyFeatures_management(lst_polylines, fc_out)


def getPolylineDict(fc_in):
    dct = {}
    flds = ("OID@", "SHAPE@")
    with arcpy.da.SearchCursor(fc_in, flds) as curs:
        for row in curs:
            dct[row[0]] = row[1]
    del row, curs
    return dct

def getFromAndToNodes(dct):
    dct_from = {}
    dct_to = {}
    for oid, polyline in dct.items():
        dct_from[oid] = polyline.firstPoint
        dct_to[oid] = polyline.lastPoint
    return dct_from, dct_to

def insertPointAtStart(polyline, pnt_found):
    sr = polyline.spatialReference
    lst_pnts = [pnt_found]
    for part in polyline:
        for pnt in part:
            lst_pnts.append(pnt)
    return arcpy.Polyline(arcpy.Array(lst_pnts), sr)

def addPointAtEnd(polyline, pnt_found):
    sr = polyline.spatialReference
    lst_pnts = []
    for part in polyline:
        for pnt in part:
            lst_pnts.append(pnt)
    lst_pnts.append(pnt_found)
    return arcpy.Polyline(arcpy.Array(lst_pnts), sr)

def calcDistance(pnt_to, pnt):
    return math.hypot(pnt_to.X - pnt.X, pnt_to.Y - pnt.Y)

if __name__ == '__main__':
    main()

If you have any questions, just let me know...

Kind regards, Xander