This is probably an extended question from my another question (Increase spatial query performance (st_difference))
This is the background is this. I have a road link and a tunnel link. From the road link, I need to erase the tunnel link out. With builtin GIS geoprocessing, I can use these tools Erase tool in ArcMap, Difference toon in QGIS.
I used ArcMap erase tool, and it seemed to work fine. with QGIS tool, some areas were fine but another areas did not work well.
I assume that major issue was the topology of two links were not the same. (It does look like but it was not).
I wonder why ArcGIS returned the answer that I want but QGIS/PostGIS didn't. Also, I would like to have exact same answer of ArcGIS erase tool in QGIS (though I know it is difference but I wonder if there are any tricks...)