I am using QGIS 2.16 and trying to compute distances between two points using the MMQGIS plug-in (Hub -distance). This worked like a charm, but recently I have been getting a Python Error whenever I change the measurement unit from "layer unit" to any of the other. The error message is:

"   Traceback (most recent call last):
              File "/Users/henry/.qgis2/python/plugins/mmqgis/mmqgis_dialogs.py",   line 1727, in run
                nameattributename, units, addlines, savename, evenly_distributed, 1)
              File "/Users/henry/.qgis2/python/plugins/mmqgis/mmqgis_library.py", line 4169, in mmqgis_hub_distance
                hubdist = mmqgis_distance(source[0], hub[0])
              File "/Users/henry/.qgis2/python/plugins/mmqgis/mmqgis_library.py", line 544, in mmqgis_distance
                start_lon = start.x() * math.pi / 180
            NameError: global name 'math' is not defined"

Does anybody know how to resolve this issue?

  • 1
    It looks like the math module is not installed properly. This is something that is installed by default when python is installed. I suggest reinstalling QGIS or python. – Fezter Oct 24 '16 at 22:07

If you want to fix it by yourself: Go to Plugin-Directory mmqgis and open the file mmqgis_library.py there you'll find the lines:

# Used instead of "import math" so math functions can be used without "math." prefix
from math import *

So, everywhere in the file, you have to delete math. in any occurence, eg. math.cos becomes just cos. Anyway, the author should be informed!!

  • Thanks a lot! It works like a charm again now. I also informed the author. – heste Oct 28 '16 at 9:25

This is almost certainly a bug in the plugin. It might be related to this SE post.

I suggest you send a bug report to the developer of the plugin.

First, though, make sure you're using an updated version of the plugin. Michael Minn is the developer: http://michaelminn.com/linux/mmqgis/

  • Thanks Alex! I did use the updated version of the plugin, changing the code resolved the issue though. – heste Oct 28 '16 at 9:27
  • Worth reporting, @heste, so that it can be fixed for others =). Ah, I see you have. Nicely done! – Alex Leith Oct 29 '16 at 7:54

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