I have recently installed the Essen version of QGIS and I am having difficulty running a query I have ran without problem on previous versions of QGIS.

I want to provide 'measurement' data to a polyline using a points layer by calibrating with LRS.

I receive the following Python Error

TypeError: object of type 'NoneType' has no len()

Is this a bug in the latest version or is there something simple I am overlooking?

  • How do you run your query? Is this a processing algorithm? Or a plugin? Commented May 10, 2017 at 13:47

1 Answer 1


I'm not familiar with the LRS plugin but that looks like it might be better to raise this as an issue on the project issues page on Github. However, it looks similar (but not identical) to an existing, closed issue.

The message is python's way of saying it's trying to calculate the len() of something (a string maybe?) and the thing it's trying to calculate doesn't exist.

You should probably check that:-

  • you've specified all required options in any dialog boxes
  • you don't have any NULL fields
  • you don't have any NULL geometries

If you brought in your points from a delimited file (e.g. exported from a spreadsheet) this can happen all too easily.

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