Currently we are working in a geological project..in which all the Contacts, Linear & some other geological features have to be captured.

The thing is most of the features have to be Captured as "Line" and then it has to be converted to "Polygon". So that we don't have to repeat the digitization for features like Contact....

1) Is it not at all possible in Qgis to Snap a line with the same line ? like that of in AutoCAD, Mapinfo..?? (Image 1)

2) I've captured a polygon as two separate lines...and when i use "Line to Polygon" (Enclose in the case of Mapinfo)....it actually creates two polygons instead of one single entity. Is it a bug ? (Image 2)

I am trying to convince some of colleagues (and the management as well) to switch over to QGIS..atleast in few systems...So i am trying to figure out the available functionalities in QGIS as that of MapInfo. So any sort of feedback will be of great help.

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Update: Polygonize command does the trick of converting the two separate lines into one single polygon feature...(Image 2).

  • Welcome to GIS.se! Please edit your question to ask only one question – you are free to ask the second one in another post! Since you've already answered (2) yourself perhaps just edit it out of this one. Thanks! – Simbamangu Apr 16 '14 at 10:42

You can snap a line to itself, but only after saving.

My workaround is to digitize the line, but set the last point a bit offset to the first point, then save, and then move the last point to the first.

As a consequnce, I start digitizing a new closed line with a point that is already created by another adjacent polygon if possible.

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  • Thanks a lot Andre....Yeah, it worked. But still it needs some tweaks to have a smooth digitization. – joseph_k Apr 16 '14 at 10:25

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