QGIS 2.12 Lines to Polygons not work properly

How do I convert lines to polygons in QGIS?

Steps to convert Polyline to Polygon on QGIS



Open the layer file that you want to convert. Then, go to Vector | Geometry Tools | Line to polygon. It will open a new conversion window. Select the source layer you want to convert in the input layer.
 

How do I fix broken geometry in QGIS?

QGIS comes with a built-in algorithm to fix geometry errors automatically. Search for and locate the Vector geometry ‣ Fix geometries algorithm. Double-click to run it.
 

Which tool is used to check the errors while polygon using a layer?

Geometry Checker is a powerful core plugin to check and fix the geometry validity of a layer.

How do I merge lines in QGIS?

Quote from video: Option go to edit geometry. And go to this uh option called merge selected features.

How do I convert a line shapefile to a polygon shapefile?

Procedure

1. Create a new empty polygon shapefile or feature class, making sure to apply the correct coordinate system.
2. Add the existing line feature and the newly created polygon layer to a map document.
3. Start an edit session, and set the target to the polygon shapefile or feature class.

How do I convert a line to a polygon in GIS?

Click the Editor drop-down, and click Start Editing. Select the polyline feature class, and click OK. Click the Select tool, and select the polyline feature to be converted to a polygon feature.
 

How do you smooth polygon lines in QGIS?

Quote from video: Tool box and we're just gonna search for smooth. And we're gonna look for smooth geometry. And make sure that you've chosen the correct shapefile if you have multiple shape files in your layers panel.

How do you smooth contour lines in QGIS?

Contour Smoothing

1. In the processing toolbox type “smooth”. The smooth tool will appear under Vector Geometry, as in figure 10. Figure 10.
2. Open the smooth tool. Select the input contour layer.
3. If all the parameters have been set. Click Run in Background button to start the smoothing process.

What is invalid geometry?

Geometry that is considered invalid meets one of the following conditions: Empty—This condition occurs when the geometry of a feature has zero points and does not contain geometric information, represented by SHAPE_LEN and SHAPE_AREA fields, beyond its original initialization state.

How do you convert line to poly?

In Ribbon View, on the Format tab, in the Picture group, click Drawing Tools, and then click Convert Lines to Polyline.

How do you make a polygon out of polylines?

To Convert Polyline Objects to Polygons

1. Set the PROXYGRAPHICS system variable to 0.
2. On the command line, enter mappolylinetopolygon. Press Enter.
3. If you already had a selection set, the selected closed polylines are converted. If you did not have a selection set, select the polylines to convert. Press Enter.

How do you convert contour to polygon?

How To: Create polygons from contour polylines in ArcMap using the Feature To Polygon tool

1. Click the Search icon. . Search for the Feature To Polygon (Data Management) tool.
2. Click the tool and configure the parameters in the Feature To Polygon dialog box.