Hybrid parallel

[Steven P]

1 hour ago, SLW210 said:

For AutoCAD, it helps if BOTH polylines go the same direction.

 I think Lee Mac had something to work out polyline direction, so should be able to check and reverse a polyline if necessary. Reverse back again after

[PGia]

4 hours ago, SLW210 said:

From what I have gathered, no easy task to do this, many GIS programs seem to struggle with pinpoint accuracy as well. 

 

The method for QGIS, is involved, so I didn't get time to run through it with the plugin, but I did dig into reddit and some GIS sites.

 

Basically they do similar method, they just add a lot of points down the "polyline/line" and run the appropriate "centerline tool".

 

Where someone posted results, I saw some in some of them the same "off center through some areas" as in the methods posted here.

 

This was apparently plenty good enough for most GIS users, though I only did a relatively quick dig.

 

In a similar method for AutoCAD, maybe adding more points to the polylines would help.

 

I might have time Monday at home to check QGIS. Though I did import the OPs drawings into a session, the first one comes in very strange, the second seemed to be correct.

 

The OP still hasn't answered why the second .dwg posted comes up as not an AutoCAD drawing.

 

For AutoCAD, it helps if BOTH polylines go the same direction.

 

I’m sorry.
I didn’t think this was important — but maybe I was wrong.
I usually copy drawings from my PC to edit them on my smartphone. The app I use on my smartphone is DWG FastView.
I don’t remember where I sent it from, but if that message appeared when opening it, it must be because I saved the drawing on my smartphone for some reason and sent it from there.