There are three issues to contend with in this case:
- Holes
- Lines between polygons
- End lines

Holes
Since any line within a hole will be maintained, remove holes from polygons. In the script below I do so by use of cursors and geometries.
Lines between polygons
Lines that touch two polygons need to be removed. In the script below I do so by performing a spatial join of one to many
, with my lines as my input feature class and my polygons as my join feature class. Any line that gets generated twice touches two polygons and is removed.
End lines
To remove lines that only touch a polygon on one end, I convert lines to end points. I then make use of feature layers and selections to determine which end points are floaters. I select the end points that intersect the polygons. I then switch my selection. This selects end points that don't intersect polygons. I select any line that intersects these selected points and delete them.
Result

Assumptions
- Inputs are file geodatabase feature classes
- ArcGIS advanced license is available (due to an
erase
and a feature vertices to points
)
- Continuous, connected lines are a single feature
- Polygons do no overlap
- There are no multipart polygons
Script
The script below outputs a feature class with the name of your line feature class plus _GreedyClip
, in the same geodatabase as your line feature class. A workspace location is also needed.
#input polygon feature class
polyFc = r"C:\Users\e1b8\Desktop\E1B8\Workspace\Workspace.gdb\testPolygon2"
#input line feature class
lineFc = r"C:\Users\e1b8\Desktop\E1B8\Workspace\Workspace.gdb\testLine"
#workspace
workspace = r"in_memory"
print "importing"
import arcpy
import os
#generate a unique ArcGIS file name
def UniqueFileName(location = "in_memory", name = "file", extension = ""):
if extension:
outName = os.path.join (location, name + "." + extension)
else:
outName = os.path.join (location, name)
i = 0
while arcpy.Exists (outName):
i += 1
if extension:
outName = os.path.join (location, "{0}_{1}.{2}".format (name, i, extension))
else:
outName = os.path.join (location, "{0}_{1}".format (name, i))
return outName
#remove holes from polygons
def RemoveHoles (inFc, workspace):
outFc = UniqueFileName (workspace)
array = arcpy.Array ()
sr = arcpy.Describe (inFc).spatialReference
outPath, outName = os.path.split (outFc)
arcpy.CreateFeatureclass_management (outPath, outName, "POLYGON", spatial_reference = sr)
with arcpy.da.InsertCursor (outFc, "SHAPE@") as iCurs:
with arcpy.da.SearchCursor (inFc, "SHAPE@") as sCurs:
for geom, in sCurs:
try:
part = geom.getPart (0)
except:
continue
for pnt in part:
if not pnt:
break
array.add (pnt)
polygon = arcpy.Polygon (array)
array.removeAll ()
row = (polygon,)
iCurs.insertRow (row)
del iCurs
del sCurs
return outFc
#split line fc by polygon fc
def SplitLinesByPolygon (lineFc, polygonFc, workspace):
#clip
clipFc = UniqueFileName(workspace)
arcpy.Clip_analysis (lineFc, polygonFc, clipFc)
#erase
eraseFc = UniqueFileName(workspace)
arcpy.Erase_analysis (lineFc, polygonFc, eraseFc)
#merge
mergeFc = UniqueFileName(workspace)
arcpy.Merge_management ([clipFc, eraseFc], mergeFc)
#multipart to singlepart
outFc = UniqueFileName(workspace)
arcpy.MultipartToSinglepart_management (mergeFc, outFc)
#delete intermediate data
for trash in [clipFc, eraseFc, mergeFc]:
arcpy.Delete_management (trash)
return outFc
#remove lines between two polygons and end lines
def RemoveLines (inFc, polygonFc, workspace):
#check if "TARGET_FID" is in fields
flds = [f.name for f in arcpy.ListFields (inFc)]
if "TARGET_FID" in flds:
#delete "TARGET_FID" field
arcpy.DeleteField_management (inFc, "TARGET_FID")
#spatial join
sjFc = UniqueFileName(workspace)
arcpy.SpatialJoin_analysis (inFc, polygonFc, sjFc, "JOIN_ONE_TO_MANY")
#list of TARGET_FIDs
targetFids = [fid for fid, in arcpy.da.SearchCursor (sjFc, "TARGET_FID")]
#target FIDs with multiple occurances
deleteFids = [dFid for dFid in targetFids if targetFids.count (dFid) > 1]
if deleteFids:
#delete rows with update cursor
with arcpy.da.UpdateCursor (inFc, "OID@") as cursor:
for oid, in cursor:
if oid in deleteFids:
cursor.deleteRow ()
del cursor
#feature vertices to points
vertFc = UniqueFileName(workspace)
arcpy.FeatureVerticesToPoints_management (inFc, vertFc, "BOTH_ENDS")
#select points intersecting polygons
arcpy.MakeFeatureLayer_management (vertFc, "vertLyr")
arcpy.SelectLayerByLocation_management ("vertLyr", "", polygonFc, "1 FEET")
#switch selection
arcpy.SelectLayerByAttribute_management ("vertLyr", "SWITCH_SELECTION")
arcpy.MakeFeatureLayer_management (inFc, "lineLyr")
#check for selection
if arcpy.Describe ("vertLyr").FIDSet:
#select lines by selected points
arcpy.SelectLayerByLocation_management ("lineLyr", "", "vertLyr", "1 FEET")
#double check selection (should always have selection)
if arcpy.Describe ("lineLyr").FIDSet:
#delete selected rows
arcpy.DeleteFeatures_management ("lineLyr")
#delete intermediate data
for trash in [sjFc, "vertLyr", "lineLyr"]:
arcpy.Delete_management (trash)
#main script
def main (polyFc, lineFc, workspace):
#remove holes
print "removing holes"
holelessPolyFc = RemoveHoles (polyFc, workspace)
#split line at polygons
print "splitting lines at polygons"
splitFc = SplitLinesByPolygon (lineFc, holelessPolyFc, workspace)
#delete unwanted lines
print "removing unwanted lines"
RemoveLines (splitFc, polyFc, workspace)
#create output feature class
outFc = lineFc + "_GreedyClip"
outFcPath, outFcName = os.path.split (outFc)
outFc = UniqueFileName (outFcPath, outFcName)
arcpy.CopyFeatures_management (splitFc, outFc)
print "created:"
print outFc
print
print "cleaning up"
#delete intermediate data
for trash in [holelessPolyFc, splitFc]:
arcpy.Delete_management (trash)
print "done"
if __name__ == "__main__":
main (polyFc, lineFc, workspace)