I have the problem that when I create a new point (in a point layer) or a new line (in a line layer of course) and I save the changes to the layer (so NOT the project save) then QGIS rounds up the coordinates of the new element to six decimals. I can see that in the "identify results" window by clicking on "(Derived"). So as a result, I don't get the required position of the new element. The layers are DB tables that I received and I just open them in QGIS. I don't know the source of the layers. The CRS of the project is the same as the CRS of the layer. The thing is, if I create a new shapefile-layer myself (point for example), the new element remains in the wanted location even after saving layer changes. So it has something to do with the layer I received. But I don't know what that is. I am trying for 3 days to find a solution and can't seem to solve the problem. Does anyone have a hint for me?

Bevore saving the layer changes: bevore save

After saving the layer changes: after save

  • What is the format of the layer that you have? Shape?
    – Nathan W
    Commented Feb 19, 2013 at 9:34
  • That's the problem. I don't know. I access the layer from a network database (MSSQL/dbo) and can't see any extension of the file. I suspect it is not a shapefile. Heard these is data translated somehow in osm format. Unfortunately i can not find out more today about the source of the layer. Any idea?
    – Tudor
    Commented Feb 19, 2013 at 9:43
  • Well I guess it's just a database layer.
    – Nathan W
    Commented Feb 19, 2013 at 10:47
  • @Nathan W that sounds plausible. But still, why does QGIS round up?
    – Tudor
    Commented Feb 19, 2013 at 11:09
  • 3
    If the geometries are stored in a database, database settings might limit the number of digits.
    – underdark
    Commented Feb 22, 2013 at 15:44

2 Answers 2


This is a bug in QGIS. I've created a bug report here.

It relates to the MS SQL data provider using WKT by default to save and update records. The QgsGeometry::exportToWkt() method rounds coordinates to 6 decimal places. In more recent versions, this has been increased to 8, but it is still rounding.


This is actually an issue with floating point calculation where in binary computers can't see recurring numbers and therefore can't round. It doesn't matter if you're in a billion dollar ArcGIS development environment or QGIS world, the issue is that you are in binary base2.

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