I did come across this bit of code, which may help:
import arcpy
import math
def scale_geom(geom, scale, reference=None):
"""Returns geom scaled to scale %"""
if geom is None: return None
if reference is None:
# we'll use the centroid if no reference point is given
reference = geom.centroid
refgeom = arcpy.PointGeometry(reference)
newparts = []
for pind in range(geom.partCount):
part = geom.getPart(pind)
newpart = []
for ptind in range(part.count):
apnt = part.getObject(ptind)
if apnt is None:
# polygon boundaries and holes are all returned in the same part.
# A null point separates each ring, so just pass it on to
# preserve the holes.
newpart.append(apnt)
continue
bdist = refgeom.distanceTo(apnt)
bpnt = arcpy.Point(reference.X + bdist, reference.Y)
adist = refgeom.distanceTo(bpnt)
cdist = arcpy.PointGeometry(apnt).distanceTo(bpnt)
# Law of Cosines, angle of C given lengths of a, b and c
angle = math.acos((adist**2 + bdist**2 - cdist**2) / (2 * adist * bdist))
scaledist = bdist * scale
# If the point is below the reference point then our angle
# is actually negative
if apnt.Y < reference.Y: angle = angle * -1
# Create a new point that is scaledist from the origin
# along the x axis. Rotate that point the same amount
# as the original then translate it to the reference point
scalex = scaledist * math.cos(angle) + reference.X
scaley = scaledist * math.sin(angle) + reference.Y
newpart.append(arcpy.Point(scalex, scaley))
newparts.append(newpart)
return arcpy.Geometry(geom.type, arcpy.Array(newparts), geom.spatialReference)You can call it with a geometry object, a scale factor (1 = same size, 0.5 = half size, 5 = 5 times as large, etc.), and an optional reference point:
scale_geom(some_geom, 1.5)
Referenced from here:
https://gis.stackexchange.com/questions/169694/is-there-arcpy-tool-for-polygon-resizing-like-scale-t...
Regards,
Mark
