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Alternatively, I've written a dice algorithm for you based on the discussion in "Optimizing ArcPy code to cut polygon?" to cut/split/dice a polygon feature class using a polyline feature class. Credits to those on the thread.

__author__ = "John K. Tran, Tristan Forward"
__contact__ = "[email protected], http://gis.stackexchange.com/users/6996/tristan-forward"
__version__ = "2.0"
__created__ = "7/3/15"
__credits__ = "http://gis.stackexchange.com/questions/124198/optimizing-arcpy-code-to-cut-polygon"

"""
Cut polygons by polylines, splitting each polygon into slices.
:param to_cut: The polygon to cut.
:param cutter: The polylines that will each polygon.
:param out_fc: The output with the split geometry added to it.
"""

import os
import sys
import arcpy

arcpy.SetProgressor("default", "Firing up script...")

to_cut = arcpy.GetParameterAsText(0)
cutter = arcpy.GetParameterAsText(1)
out_fc = arcpy.GetParameterAsText(2)

spatialref = arcpy.Describe(to_cut).spatialReference
polygons = []
lines = []
slices = []
gcount = 0

pcount = 0
with arcpy.da.SearchCursor(to_cut, ["SHAPE@", "OID@"]) as pcursor:
    for prow in pcursor:
        arcpy.SetProgressorLabel("Generating slices: {0} rows complete".format(str(pcount)))
        polygon = prow[0]
        polyid = prow[1]
        polygons.append((polygon, polyid))
        pcount += 1
del pcursor

lcount= 0
with arcpy.da.SearchCursor(cutter, ["SHAPE@", "OID@"]) as lcursor:
    for lrow in lcursor:
        line = lrow[0]
        lineid = lrow[1]
        lines.append((line, lineid))
        lcount += 1
del lcursor

def cut_geometry():
    global polygons
    global lines
    global slices
    global gcount
    for eachpoly, eachpolyid in polygons:
        iscut = False
        for eachline, eachlineid in lines:
            if eachline.crosses(eachpoly):
                try:
                    slice1, slice2 = eachpoly.cut(eachline)
                    polygons.insert(0, (slice1, eachpolyid))
                    polygons.insert(0, (slice2, eachpolyid))
                    iscut = True
                except RuntimeError:
                    continue
        if iscut == False:
            slices.append((eachpoly, eachpolyid))
            gcount += 1
            if gcount % 10 == 0:
                arcpy.SetProgressorLabel("Cutting polygons: {0} rows complete".format(str(gcount)))
        polygons.remove((eachpoly, eachpolyid))

while polygons:
    cut_geometry()

arcpy.SetProgressorLabel("Creating output feature class")
arcpy.CreateFeatureclass_management(os.path.dirname(out_fc), os.path.basename(out_fc), "POLYGON",
                                    spatial_reference = spatialref)
arcpy.AddField_management(out_fc, "SOURCE_OID", "LONG")
scount = 0
with arcpy.da.InsertCursor(out_fc, ["SHAPE@", "SOURCE_OID"]) as icursor:
    for eachslice in slices:
        if scount % 10 == 0:
            arcpy.SetProgressorLabel("Inserting slices: {0} rows complete".format(str(scount)))
        icursor.insertRow(eachslice)
        scount += 1
del icursor

arcpy.SetProgressorLabel("Deleting duplicate slices")
shapefieldname = arcpy.Describe(out_fc).shapeFieldName
arcpy.DeleteIdentical_management(out_fc, [shapefieldname, "SOURCE_OID"])

arcpy.ResetProgressor()

Alternatively, I've written a dice algorithm for you based on the discussion in "Optimizing ArcPy code to cut polygon?" to cut/split/dice a polygon feature class using a polyline feature class. Credits to those on the thread.

__author__ = "John K. Tran, Tristan Forward"
__contact__ = "[email protected], https://gis.stackexchange.com/users/6996/tristan-forward"
__version__ = "2.0"
__created__ = "7/3/15"
__credits__ = "https://gis.stackexchange.com/questions/124198/optimizing-arcpy-code-to-cut-polygon"

"""
Cut polygons by polylines, splitting each polygon into slices.
:param to_cut: The polygon to cut.
:param cutter: The polylines that will each polygon.
:param out_fc: The output with the split geometry added to it.
"""

import os
import sys
import arcpy

arcpy.SetProgressor("default", "Firing up script...")

to_cut = arcpy.GetParameterAsText(0)
cutter = arcpy.GetParameterAsText(1)
out_fc = arcpy.GetParameterAsText(2)

spatialref = arcpy.Describe(to_cut).spatialReference
polygons = []
lines = []
slices = []
gcount = 0

pcount = 0
with arcpy.da.SearchCursor(to_cut, ["SHAPE@", "OID@"]) as pcursor:
    for prow in pcursor:
        arcpy.SetProgressorLabel("Generating slices: {0} rows complete".format(str(pcount)))
        polygon = prow[0]
        polyid = prow[1]
        polygons.append((polygon, polyid))
        pcount += 1
del pcursor

lcount= 0
with arcpy.da.SearchCursor(cutter, ["SHAPE@", "OID@"]) as lcursor:
    for lrow in lcursor:
        line = lrow[0]
        lineid = lrow[1]
        lines.append((line, lineid))
        lcount += 1
del lcursor

def cut_geometry():
    global polygons
    global lines
    global slices
    global gcount
    for eachpoly, eachpolyid in polygons:
        iscut = False
        for eachline, eachlineid in lines:
            if eachline.crosses(eachpoly):
                try:
                    slice1, slice2 = eachpoly.cut(eachline)
                    polygons.insert(0, (slice1, eachpolyid))
                    polygons.insert(0, (slice2, eachpolyid))
                    iscut = True
                except RuntimeError:
                    continue
        if iscut == False:
            slices.append((eachpoly, eachpolyid))
            gcount += 1
            if gcount % 10 == 0:
                arcpy.SetProgressorLabel("Cutting polygons: {0} rows complete".format(str(gcount)))
        polygons.remove((eachpoly, eachpolyid))

while polygons:
    cut_geometry()

arcpy.SetProgressorLabel("Creating output feature class")
arcpy.CreateFeatureclass_management(os.path.dirname(out_fc), os.path.basename(out_fc), "POLYGON",
                                    spatial_reference = spatialref)
arcpy.AddField_management(out_fc, "SOURCE_OID", "LONG")
scount = 0
with arcpy.da.InsertCursor(out_fc, ["SHAPE@", "SOURCE_OID"]) as icursor:
    for eachslice in slices:
        if scount % 10 == 0:
            arcpy.SetProgressorLabel("Inserting slices: {0} rows complete".format(str(scount)))
        icursor.insertRow(eachslice)
        scount += 1
del icursor

arcpy.SetProgressorLabel("Deleting duplicate slices")
shapefieldname = arcpy.Describe(out_fc).shapeFieldName
arcpy.DeleteIdentical_management(out_fc, [shapefieldname, "SOURCE_OID"])

arcpy.ResetProgressor()

__author__ = "John K. Tran, Tristan Forward"
__contact__ = "[email protected], http://gis.stackexchange.com/users/6996/tristan-forward"
__version__ = "2.0"
__created__ = "7/3/15"
__credits__ = "http://gis.stackexchange.com/questions/124198/optimizing-arcpy-code-to-cut-polygon"

"""
Cut polygons by polylines, splitting each polygon into slices.
:param to_cut: The polygon to cut.
:param cutter: The polylines that will each polygon.
:param out_fc: The output with the split geometry added to it.
"""

import os
import sys
import arcpy

arcpy.SetProgressor("default", "Firing up script...")

to_cut = arcpy.GetParameterAsText(0)
cutter = arcpy.GetParameterAsText(1)
out_fc = arcpy.GetParameterAsText(2)

spatialref = arcpy.Describe(to_cut).spatialReference
polygons = []
lines = []
slices = []
gcount = 0

pcount = 0
with arcpy.da.SearchCursor(to_cut, ["SHAPE@", "OID@"]) as pcursor:
    for prow in pcursor:
        arcpy.SetProgressorLabel("Generating slices: {0} rows complete".format(str(pcount)))
        polygon = prow[0]
        polyid = prow[1]
        polygons.append((polygon, polyid))
        pcount += 1
del pcursor

lcount= 0
with arcpy.da.SearchCursor(cutter, ["SHAPE@", "OID@"]) as lcursor:
    for lrow in lcursor:
        line = lrow[0]
        lineid = lrow[1]
        lines.append((line, lineid))
        lcount += 1
del lcursor

def cut_geometry():
    global polygons
    global lines
    global slices
    global gcount
    for eachpoly, eachpolyid in polygons:
        iscut = False
        for eachline, eachlineid in lines:
            if eachline.crosses(eachpoly):
                try:
                    slice1, slice2 = eachpoly.cut(eachline)
                    polygons.insert(0, (slice1, eachpolyid))
                    polygons.insert(0, (slice2, eachpolyid))
                    iscut = True
                except RuntimeError:
                    continue
        if iscut == False:
            slices.append((eachpoly, eachpolyid))
            gcount += 1
            if gcount % 10 == 0:
                arcpy.SetProgressorLabel("Cutting polygons: {0} rows complete".format(str(gcount)))
        polygons.remove((eachpoly, eachpolyid))

while polygons:
    cut_geometry()

arcpy.SetProgressorLabel("Creating output feature class")
arcpy.CreateFeatureclass_management(os.path.dirname(out_fc), os.path.basename(out_fc), "POLYGON",
                                    spatial_reference = spatialref)
arcpy.AddField_management(out_fc, "SOURCE_OID", "LONG")
scount = 0
with arcpy.da.InsertCursor(out_fc, ["SHAPE@", "SOURCE_OID"]) as icursor:
    for eachslice in slices:
        if scount % 10 == 0:
            arcpy.SetProgressorLabel("Inserting slices: {0} rows complete".format(str(scount)))
        icursor.insertRow(eachslice)
        scount += 1
del icursor

arcpy.SetProgressorLabel("Deleting duplicate slices")
shapefieldname = arcpy.Describe(out_fc).shapeFieldName
arcpy.DeleteIdentical_management(out_fc, [shapefieldname, "SOURCE_OID"])

arcpy.ResetProgressor()

__author__ = "John K. Tran, Tristan Forward"
__contact__ = "[email protected], http://gis.stackexchange.com/users/6996/tristan-forward"
__version__ = "2.0"
__created__ = "7/3/15"
__credits__ = "http://gis.stackexchange.com/questions/124198/optimizing-arcpy-code-to-cut-polygon"

"""
Cut polygons by polylines, splitting each polygon into slices.
:param to_cut: The polygon to cut.
:param cutter: The polylines that will each polygon.
:param out_fc: The output with the split geometry added to it.
"""

import os
import sys
import arcpy

arcpy.SetProgressor("default", "Firing up script...")

to_cut = arcpy.GetParameterAsText(0)
cutter = arcpy.GetParameterAsText(1)
out_fc = arcpy.GetParameterAsText(2)

spatialref = arcpy.Describe(to_cut).spatialReference
polygons = []
lines = []
slices = []
gcount = 0

pcount = 0
with arcpy.da.SearchCursor(to_cut, ["SHAPE@", "OID@"]) as pcursor:
    for prow in pcursor:
        arcpy.SetProgressorLabel("Generating slices: {0} rows complete".format(str(pcount)))
        polygon = prow[0]
        polyid = prow[1]
        polygons.append((polygon, polyid))
        pcount += 1
del pcursor

lcount= 0
with arcpy.da.SearchCursor(cutter, ["SHAPE@", "OID@"]) as lcursor:
    for lrow in lcursor:
        line = lrow[0]
        lineid = lrow[1]
        lines.append((line, lineid))
        lcount += 1
del lcursor

def cut_geometry():
    global polygons
    global lines
    global slices
    global gcount
    for eachpoly, eachpolyid in polygons:
        iscut = False
        for eachline, eachlineid in lines:
            if eachline.crosses(eachpoly):
                try:
                    slice1, slice2 = eachpoly.cut(eachline)
                    polygons.insert(0, (slice1, eachpolyid))
                    polygons.insert(0, (slice2, eachpolyid))
                    iscut = True
                except RuntimeError:
                    continue
        if iscut == False:
            slices.append((eachpoly, eachpolyid))
            gcount += 1
            if gcount % 10 == 0:
                arcpy.SetProgressorLabel("Cutting polygons: {0} rows complete".format(str(gcount)))
        polygons.remove((eachpoly, eachpolyid))

while polygons:
    cut_geometry()

arcpy.SetProgressorLabel("Creating output feature class")
arcpy.CreateFeatureclass_management(os.path.dirname(out_fc), os.path.basename(out_fc), "POLYGON",
                                    spatial_reference = spatialref)
arcpy.AddField_management(out_fc, "SOURCE_OID", "LONG")
scount = 0
with arcpy.da.InsertCursor(out_fc, ["SHAPE@", "SOURCE_OID"]) as icursor:
    for eachslice in slices:
        if scount % 10 == 0:
            arcpy.SetProgressorLabel("Inserting slices: {0} rows complete".format(str(scount)))
        icursor.insertRow(eachslice)
        scount += 1
del icursor

arcpy.SetProgressorLabel("Deleting duplicate slices")
shapefieldname = arcpy.Describe(out_fc).shapeFieldName
arcpy.DeleteIdentical_management(out_fc, [shapefieldname, "SOURCE_OID"])

arcpy.ResetProgressor()

Alternatively, I've written a quick script based on the discussion in "Optimizing ArcPy code to cut polygon?" to cut/split/dice a polygon feature class using a polyline feature class. Credits to those on the thread.

• Your polyline must cross the polygon entirely, no stopping halfway or passing off to a second line inside the polygon to finish off the traverse.
• If a polygon gets crossed by two (or more) lines, it will get cut twice and you'll get some stacked polygons, since you end up with 4 slices at the end (see images).

__author__ = "John K. Tran, Tristan Forward"
__contact__ = "[email protected], http://gis.stackexchange.com/users/6996/tristan-forward"
__version__ = "1.0"
__created__ = "7/3/15"
__credits__ = "http://gis.stackexchange.com/questions/124198/optimizing-arcpy-code-to-cut-polygon"

import os
import sys
import arcpy

def cut_geometry(to_cut, cutter, out_fc):
    """
    Cut polygons by polylines, splitting each polygon into slices.
    :param to_cut: The polygon to cut.
    :param cutter: The polylines that will each polygon.
    :param out_fc: The output with the split geometry added to it.
    """
    
    arcpy.SetProgressor("default", "Firing up script...")
    geometries = None
    polygon = None
    spatialref = arcpy.Describe(to_cut).spatialReference
    slices = []
 
    pcount = 0
    with arcpy.da.SearchCursor(to_cut, ["SHAPE@", "OID@"]) as pcursor:
        for prow in pcursor:
            arcpy.SetProgressorLabel("Generating slices: {0} rows complete".format(str(pcount)))
            polygon = prow[0]
            polyid = prow[1]
            with arcpy.da.SearchCursor(cutter, "SHAPE@") as lcursor:
                for lrow in lcursor:
                    line = lrow[0]
                    if line.crosses(polygon):
                        try:
                            slice1, slice2 = polygon.cut(line)
                        except RuntimeError:
                            continue
                        slices.append((slice1, polyid))
                        slices.append((slice2, polyid))
            pcount += 1
            del lcursor
    del pcursor

    arcpy.SetProgressorLabel("Creating output feature class")
    arcpy.CreateFeatureclass_management(os.path.dirname(out_fc), os.path.basename(out_fc), "POLYGON", spatial_reference = spatialref)
    arcpy.AddField_management(out_fc, "SOURCE_OID", "LONG")
    scount = 0
    with arcpy.da.InsertCursor(out_fc, ["SHAPE@", "SOURCE_OID"]) as icursor:
        for eachslice in slices:
            if scount % 10 == 0:
                arcpy.SetProgressorLabel("Inserting slices: {0} rows complete".format(str(scount)))
            icursor.insertRow(eachslice)
            scount += 1
    del icursor

    arcpy.ResetProgressor()

if __name__ == '__main__':
    argv = tuple(arcpy.GetParameterAsText(i) for i in range(arcpy.GetArgumentCount()))
    cut_geometry(*argv)

The script isn't too slow, but for others who want improve the script, there may be some value in exploring using Extent objects. I think line.crosses(polygon) does the job before performing polygon.cut(line), but maybe Extents are a good alternative to explore.

Alternatively, I've written a dice algorithm for you based on the discussion in "Optimizing ArcPy code to cut polygon?" to cut/split/dice a polygon feature class using a polyline feature class. Credits to those on the thread.

• Your polyline must cross the polygon entirely, no stopping halfway or passing off to a second line inside the polygon to finish off the traverse.
• If you have multi-part polygons, the resulting slices will also sometimes be multi-part, since they inherit the partitioning of their parents. Self-intersecting polygons are fine and have no issue.

__author__ = "John K. Tran, Tristan Forward"
__contact__ = "[email protected], http://gis.stackexchange.com/users/6996/tristan-forward"
__version__ = "2.0"
__created__ = "7/3/15"
__credits__ = "http://gis.stackexchange.com/questions/124198/optimizing-arcpy-code-to-cut-polygon"

"""
Cut polygons by polylines, splitting each polygon into slices.
:param to_cut: The polygon to cut.
:param cutter: The polylines that will each polygon.
:param out_fc: The output with the split geometry added to it.
"""

import os
import sys
import arcpy

arcpy.SetProgressor("default", "Firing up script...")

to_cut = arcpy.GetParameterAsText(0)
cutter = arcpy.GetParameterAsText(1)
out_fc = arcpy.GetParameterAsText(2)

spatialref = arcpy.Describe(to_cut).spatialReference
polygons = []
lines = []
slices = []
gcount = 0

pcount = 0
with arcpy.da.SearchCursor(to_cut, ["SHAPE@", "OID@"]) as pcursor:
    for prow in pcursor:
        arcpy.SetProgressorLabel("Generating slices: {0} rows complete".format(str(pcount)))
        polygon = prow[0]
        polyid = prow[1]
        polygons.append((polygon, polyid))
        pcount += 1
del pcursor

lcount= 0
with arcpy.da.SearchCursor(cutter, ["SHAPE@", "OID@"]) as lcursor:
    for lrow in lcursor:
        line = lrow[0]
        lineid = lrow[1]
        lines.append((line, lineid))
        lcount += 1
del lcursor

def cut_geometry():
    global polygons
    global lines
    global slices
    global gcount
    for eachpoly, eachpolyid in polygons:
        iscut = False
        for eachline, eachlineid in lines:
            if eachline.crosses(eachpoly):
                try:
                    slice1, slice2 = eachpoly.cut(eachline)
                    polygons.insert(0, (slice1, eachpolyid))
                    polygons.insert(0, (slice2, eachpolyid))
                    iscut = True
                except RuntimeError:
                    continue
        if iscut == False:
            slices.append((eachpoly, eachpolyid))
            gcount += 1
            if gcount % 10 == 0:
                arcpy.SetProgressorLabel("Cutting polygons: {0} rows complete".format(str(gcount)))
        polygons.remove((eachpoly, eachpolyid))

while polygons:
    cut_geometry()

arcpy.SetProgressorLabel("Creating output feature class")
arcpy.CreateFeatureclass_management(os.path.dirname(out_fc), os.path.basename(out_fc), "POLYGON",
                                    spatial_reference = spatialref)
arcpy.AddField_management(out_fc, "SOURCE_OID", "LONG")
scount = 0
with arcpy.da.InsertCursor(out_fc, ["SHAPE@", "SOURCE_OID"]) as icursor:
    for eachslice in slices:
        if scount % 10 == 0:
            arcpy.SetProgressorLabel("Inserting slices: {0} rows complete".format(str(scount)))
        icursor.insertRow(eachslice)
        scount += 1
del icursor

arcpy.SetProgressorLabel("Deleting duplicate slices")
shapefieldname = arcpy.Describe(out_fc).shapeFieldName
arcpy.DeleteIdentical_management(out_fc, [shapefieldname, "SOURCE_OID"])

arcpy.ResetProgressor()