topic Re: What is the correct way to use measureOnLine attribute for polyline? in Python Questions

What is the correct way to use measureOnLine attribute for polyline?

CharithKarandana — Sun, 28 Oct 2018 06:53:08 GMT

I created a polyline myself and testing the measureOnLine attribute to use it in another script which goes with real data. "polyline.measureOnLine((x, y))" doesn't work ("I'm pretty much sure the point (x,y) is on the polyline. The funny thing is

"polyline.measureOnLine(polyline.positionAlongLine(length))" works (Although there is no use of such). So I believe there is something is missing form me. Can anyone help me to overcome this?

Re: What is the correct way to use measureOnLine attribute for polyline?

CharithKarandana — Sun, 28 Oct 2018 08:15:53 GMT

One thing to add, I just found the 'queryPointAndDistance' brings the same error! It's called 'ValueError'

Re: What is the correct way to use measureOnLine attribute for polyline?

DanPatterson_Retired — Sun, 28 Oct 2018 10:38:23 GMT

Polyline—ArcPy classes | ArcGIS Desktop

measureOnLine (in_point, {use_percentage})

in_point has to be a point object and use_percentage is a boolean.

Your 'ValueError' is because you didn't provide the required object

So you need to make a point or use a point from some other object

ie arcpy.Point(x, y)

where x, y are coordinates.

Point—ArcPy classes | ArcGIS Desktop

You need to explore the arcpy section of the help to piece the useage together

Re: What is the correct way to use measureOnLine attribute for polyline?

CharithKarandana — Sun, 28 Oct 2018 15:20:25 GMT

Thanks for your response and I'm sorry to say I tried both these. It didn't work.

This was the line in my script which returned with the ffollowing error

polyline.queryPointAndDistance(startPoint)

File "C:\Program Files (x86)\ArcGIS\Desktop10.5\ArcPy\arcpy\arcobjects\arcobjects.py", line 791, in queryPointAndDistance
return convertArcObjectToPythonObject(self._arc_object.QueryPointAndDistance(*gp_fixargs((in_point, use_percentage))))
ValueError: [422809.7100999998, 845539.4996000007]

Same happens to the measureOnLine.

Re: What is the correct way to use measureOnLine attribute for polyline?

CharithKarandana — Sun, 28 Oct 2018 15:39:29 GMT

I was wrong. Your reply helped me to understand my error. Thank you very much.