Hi FME Community,
I'm trying to create an arc from two Points and a radius:
The radius can be concave or convex depending on the radius sign (negative or positive)
Anyone got any ideas how that can be done using FME?
Thanks in advance
This post is closed to further activity.
It may be an old question, an answered question, an implemented idea, or a notification-only post.
Please check post dates before relying on any information in a question or answer.
For follow-up or related questions, please post a new question or idea.
If there is a genuine update to be made, please contact us and request that the post is reopened.
It may be an old question, an answered question, an implemented idea, or a notification-only post.
Please check post dates before relying on any information in a question or answer.
For follow-up or related questions, please post a new question or idea.
If there is a genuine update to be made, please contact us and request that the post is reopened.
- 7843 replies
Hi, the FMEArc class from Python FME Objects API has a constructor which creates an Arc instance from two points, radius and whether to create counter-clockwise. See the API document.
init(twoPoints, radius, counterClockwise)
Creates an arc using the 2 points contained in the tuple, and the supplied ‘radius’ and points. startPoint and endPoint (twoPoints[0] and twoPoints[1]) must not be None.
Parameters:
twoPoints (tuple[FMEPoint]) – The tuple containing 2 points to create the arc in the form (startPoint, endPoint).
radius (float) – The radius value for the arc to be created.
counterClockwise (bool) – Whether to create a counter-clockwise arc.
A PythonCaller with this script might help you.
import fmeobjects
def createArc(feature):
x1 = float(feature.getAttribute('X1'))
y1 = float(feature.getAttribute('Y1'))
x2 = float(feature.getAttribute('X2'))
y2 = float(feature.getAttribute('Y2'))
twoPoints = (fmeobjects.FMEPoint(x1, y1), fmeobjects.FMEPoint(x2, y2))
radius = float(feature.getAttribute('Radius'))
feature.setGeometry(fmeobjects.FMEArc(twoPoints, abs(radius), 0 < radius))
Hi, the FMEArc class from Python FME Objects API has a constructor which creates an Arc instance from two points, radius and whether to create counter-clockwise. See the API document.
init(twoPoints, radius, counterClockwise)
Creates an arc using the 2 points contained in the tuple, and the supplied ‘radius’ and points. startPoint and endPoint (twoPoints[0] and twoPoints[1]) must not be None.
Parameters:
twoPoints (tuple[FMEPoint]) – The tuple containing 2 points to create the arc in the form (startPoint, endPoint).
radius (float) – The radius value for the arc to be created.
counterClockwise (bool) – Whether to create a counter-clockwise arc.
A PythonCaller with this script might help you.
import fmeobjects
def createArc(feature):
x1 = float(feature.getAttribute('X1'))
y1 = float(feature.getAttribute('Y1'))
x2 = float(feature.getAttribute('X2'))
y2 = float(feature.getAttribute('Y2'))
twoPoints = (fmeobjects.FMEPoint(x1, y1), fmeobjects.FMEPoint(x2, y2))
radius = float(feature.getAttribute('Radius'))
feature.setGeometry(fmeobjects.FMEArc(twoPoints, abs(radius), 0 < radius))
Hi, and thanks @takashi
Will that work if radius is set to large number as 3000?
- 7843 replies
Hi, the FMEArc class from Python FME Objects API has a constructor which creates an Arc instance from two points, radius and whether to create counter-clockwise. See the API document.
init(twoPoints, radius, counterClockwise)
Creates an arc using the 2 points contained in the tuple, and the supplied ‘radius’ and points. startPoint and endPoint (twoPoints[0] and twoPoints[1]) must not be None.
Parameters:
twoPoints (tuple[FMEPoint]) – The tuple containing 2 points to create the arc in the form (startPoint, endPoint).
radius (float) – The radius value for the arc to be created.
counterClockwise (bool) – Whether to create a counter-clockwise arc.
A PythonCaller with this script might help you.
import fmeobjects
def createArc(feature):
x1 = float(feature.getAttribute('X1'))
y1 = float(feature.getAttribute('Y1'))
x2 = float(feature.getAttribute('X2'))
y2 = float(feature.getAttribute('Y2'))
twoPoints = (fmeobjects.FMEPoint(x1, y1), fmeobjects.FMEPoint(x2, y2))
radius = float(feature.getAttribute('Radius'))
feature.setGeometry(fmeobjects.FMEArc(twoPoints, abs(radius), 0 < radius))
No problem for large radius.
It doesn't work only when the absolute value of radius is less than half of the distance between two points.
Got a reply from one of my collegues (thanks Daniel Kroon) which gives a very good result:
import fme
import fmeobjects
import math
def processFeature(feature):
"""Set the geometry of the feature, either as arc or line, depending on specified Radius.
Expects the following feature attributes to be present: 'X1','Y1','X2','Y2','Radius'
Zero radius creates and sets a line-geometry
Positive radius creates a counter-clockwise arc-geometry.
Negative radius creates a clockwise arc-geometry.
Feature attribute _used_arc_radius contains the actual radius being used when creating the geometry.
"""
# Get coordinates and radius from feature attributes
coords = tuple(map(lambda c: float(feature.getAttribute(c)), ['X1','Y1','X2','Y2']))
radius = float(feature.getAttribute('Radius'))
# Create an arc if radius is other than 0, else create a straight line
if(abs(radius)):
# Create point geometry
twoPoints = tuple(map(lambda c: fmeobjects.FMEPoint(*c), zip(coords[::2],coords[1::2])))
# Calculate the minimul allowed radius for an arc given two points
min_allowed_radius = round(math.sqrt((coords[0]-coords[2])**2+(coords[1]-coords[3])**2)/2,0)
# Create and set arc geometery
use_arc_radius = max(abs(radius),min_allowed_radius)
feature.setGeometry(fmeobjects.FMEArc(twoPoints, use_arc_radius, 0 > radius))
feature.setAttribute('_used_arc_radius',use_arc_radius)
else:
# Create and set arc geometery
feature.setGeometry(fmeobjects.FMELine(list(zip(coords[::2],coords[1::2]))))
feature.setAttribute('_used_arc_radius',0)