# Editing polylines in QGIS (extend, trim, fillet etc)

I was wondering, if its possible to edit lines and polylines in qgis, in similiar way as autocad commands "extend", "trim" and "fillet"?

About how the commands for in Autocad, very shortly: The EXTEND command allows you to extend an entity to touch another entity in a drawing. The TRIM command allows you to shorten an entity to an intersection or remove a section of an entity between two intersections. Fillet: Constructs an arc of specified radius between two lines, arcs, circles, or will create arcs of the specified radius at the vertices of a polyline. Radius of the arc to be constructed may be set to 0, which will make a sharp corner.

I am updating certain trailpath map and the accuracy isnt really issue - so i could just use snap and digitize/split & delete, but I began to wonder if there is for example plugin to do this in more efficient way?

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I'm not sure of how "extend", "trim" and "fillet" work in AutoCAD, maybe you could explain it a bit. Nevertheless, have you tried cadtools? –  Alexandre Neto Nov 20 '12 at 17:00
Thank you for the plugin tip, ill be sure to check that out. –  iippo Nov 20 '12 at 17:20
An afterthought: It would be great, if qgis snapping options were bit more advanced (similiar to autocad \o/). For example pretty basic snapping options like snap to: Midpoint, intersection and perpendicular would help greatly. Its really too bad I do not have any coding skills whatsoever, as I really would like to help with that kind of think if I just had the skills. –  iippo Nov 21 '12 at 7:55
Well, one can always learn to code. I'm trying that myself :-P. Remember that there are other ways to contribute, companies can always pay developers to create a specific tool or features, the values payed will probably be a lot cheaper than the cost of any proprietary licence. –  Alexandre Neto Nov 21 '12 at 9:21

## 2 Answers

To trim a line, you could simply use the 'split features' tool.

To extend, you have two choices: create a new line and merge both or use the node tool to drag the endpoint to your desired location.

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Hi - this is actually just what I did in the end. However, its not what I WANTED to do. Simply because as I drag the nodes by free hand, I wont be able to keep the line direction exactly same and will change more or less. Luckily in this particular project its wasnt a problem. However, had I been working with stuff like real estate/lot borders, this would be a serious issue in my opinion. –  iippo Nov 30 '12 at 9:13
@iippo is true. The direction can't be kept intact, if we use just the node tool. I did a trick anyway by adding a node just before the final node. Then select and drag the final node to the desired snap position. –  mapsir Feb 5 '14 at 5:21

I found CadInput plugin [1] helpful in extending (parallel mode) and making a fillet. To fillet a polygon use Reshape Features tool and set d to desired fillet distance.

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