.DXF Arc or Circle accuracy problem in QGIS or ArcGIS

المشرف العام

Administrator
طاقم الإدارة
I need to use a .DXF in either QGIS or ArcGIS.

However, if an Arc occurs in a .DXF drawing and if this file is opened in QGIS, I noticed that the geometry of the Arc is simplified. I did a test:

  • draw circles in LibreCAD and save as .DXF (I uploaded it here)
  • open in QGIS
  • convert to shapefile
  • edit shape
The circles, regardless of their size are approximated by 90 segments, so a 4-degree long circle segment is represented by a straight line. In my application this causes significant deviations (>25cm) in a canal design project...

I tried the same in ArcGIS. There, the simplification depends on the circle size - small circles have fewer segments, larger circles have more. So, in my case (for the kilometer long radius in canal bends) ArcGIS seems like the better choice.

As a side note: In ArcGIS the Arc of the .DXF is not simplified when visualized - the display of the .DXF seems correct when overlying with the exported shapefile. Within ArcGIS this would make at least snapping and digitization in higher accuracy possible.

I am a beginner in using .DXF files in GIS, but I feel this should be a popular problem. Though, after searching for a while I could not find a hint anywhere. I still fear I may miss something obvious... In case not, does anybody have a workaround for this?



أكثر...
 
أعلى