[GIS] Collapsing multiple lines into single line

arcgis-desktopgeneralizationNetworksimplify

I need to create a route (line) feature class from another feature class that contains multiple lines making up the same route.

pic 1 shows the original feature class with the multiple lines.

enter image description here

pic 2 shows the 10 ft buffer I created around the lines. Preferably, the lines that fall within a buffer would become a single line (route).

enter image description here

I've been working on this for several days, and so far none of the tools/methods I've used have yielded the appropriate results. I've tried dissolve, merge, and generalize. I tried creating a center-line from the buffers; that also didn't yield good results. Manual editing is out of the question as this is a network for the entire nation and it would take too long.

The best result so far I've gotten with a tool called Integrate. Even so, it's not completely accurate. (see pictures bellow)

before Integrate:

enter image description here

after Integrate:

enter image description here

As you can see, much better! Many of the lines have been collapsed into a single line. However, it's still not as accurate as I would hope.

Best Answer

It requires and Advanced License (and according to the help 'with ArcInfo Workstation installed') but there is a tool called Collapse Dual Lines To Centerline in the Generalization tools that essentially does what you want. It does have similar issues in terms of complicated intersections (note the 'how it works' link at the top).

To some degree any automated tool is going to have issues like those shown in your screenshots because of the complex nature of intersections and dual carriageways and such.

Related Solutions

ArcGIS Leader Lines – How to Create Multiple Leader Lines on One Annotation in ArcGIS

A very similar question was asked over at Ask A Cartographer and the answer was:

There's not even a hard way to do this yet. If you've got a lot of these, I would suggest making a line feature class and just add line features for the leaders. You'll have a lot more control over where the leaders meet the text as well.

There is also an ArcGIS Idea for Multi-leader-line balloon/callout boxes to which you could add your vote.

[GIS] Drawing parallel lines inside polygons (Well Paths) using ArcGIS Desktop

As @cndnflyr mentions, this can be scripted in Python.

Script Tool UI:

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Sample Output: enter image description here

# import libraries
import arcpy

# set input/output parameters
polyFC = arcpy.GetParameterAsText(0)        # input polygons
outParallel = arcpy.GetParameterAsText(1)   # output parallel lines
lineSpacing = arcpy.GetParameterAsText(2)   # line spacing
buffDist = arcpy.GetParameterAsText(3)      # inner buffer distance

# parse numbers from parameters
lineSpaceNum = float(lineSpacing.split(' ')[0])
buffNum = float(buffDist.split(' ')[0])

# establish spatial reference
desc = arcpy.Describe(polyFC)
SR = desc.spatialReference

# set overwrite environment
arcpy.env.overwriteOutput = True
arcpy.env.outputCoordinateSystem = SR

parallels = []
# loop through each input shape
for row in arcpy.da.SearchCursor(polyFC, ["SHAPE@"], spatial_reference=SR):

    # create inner buffer
    polyBuff = row[0].buffer(buffNum * -1)

    # create hull rectangle to establish a rotated area of interest
    coordSplit = row[0].hullRectangle.split(' ')

    # collect corner coordinates
    coordList = arcpy.Array([arcpy.Point(coordSplit[0],coordSplit[1]),arcpy.Point(coordSplit[2],coordSplit[3]),arcpy.Point(coordSplit[4],coordSplit[5]),arcpy.Point(coordSplit[6],coordSplit[7]),arcpy.Point(coordSplit[0],coordSplit[1])])

    # create lines from hull rectangle
    currentLines = []
    for pointNum in range(0,4):
        arcpy.Array([coordList.getObject(pointNum),coordList.getObject(pointNum+1)])
        hullRecLine = arcpy.Polyline(arcpy.Array([coordList.getObject(pointNum),coordList.getObject(pointNum+1)]))
        currentLines.append(hullRecLine)

    # compare first and second line to determine if first line is short or long
    firstLong = 0
    if currentLines[0].length > currentLines[1].length:
        firstLong = 1

    # calculate number of points needed along short axis
    numPoints = int(math.floor(currentLines[firstLong].length/lineSpaceNum))

    # create and join points to create parallel lines
    for point in range(1,numPoints+1):
        shortPoint1 = currentLines[firstLong].positionAlongLine(lineSpaceNum*point)
        shortPoint2 = currentLines[firstLong + 2].positionAlongLine(currentLines[firstLong + 2].length - (lineSpaceNum*point))
        parallel = arcpy.Polyline(arcpy.Array([shortPoint1.centroid,shortPoint2.centroid]), SR)

        # intersect parallel lines with buffer
        parallelBuff = parallel.intersect(polyBuff,2)
        parallels.append(parallelBuff)

# write geometries to disk
arcpy.CopyFeatures_management(parallels, outParallel)

# add to map
mxd = arcpy.mapping.MapDocument("CURRENT")
dataFrame = arcpy.mapping.ListDataFrames(mxd, "*")[0]
addLayer = arcpy.mapping.Layer(outParallel)
arcpy.mapping.AddLayer(dataFrame, addLayer)

del row

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