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

arcgis-desktoparcpy

I would like to take a polygon feature class with multiple irregular polygons, and have Arc draw parallel lines inside of each polygon. Ideally, it would be nice for Arc to figure out the angle of the longest side of the polygon and draw parallel lines to that side, but to keep it simple, I think if I could just enter one angle for all the parallel lines, that would be easier.

So line angle, width between lines, min/max length, and buffer width from the sides of the polygons are what my basic criteria are.

Image attached if that helps.

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Best Answer

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

Script Tool UI:

enter image description here

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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