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I am new to QGIS.

I would like to draw a boundary and a few polygons (to represent buildings or concreted areas) on a map for planning out a farm soil delineation map (with some irrigation). I was planning on drawing polylines to include pathways and rivers.

I wanted the map to display the surrounding roads, so I tried to include some map information using the instructions from the following tutorial.

http://www.qgistutorials.com/en/docs/making_a_map.html

Using another online resource, I then tried to draw polygons using Shapefile layer.

https://github.com/mtop/speciesgeocoder/wiki/Tutorial-for-creating-polygons-in-QGIS

However, I am facing an obstacle now as the method provided works for drawing one polygon only. When I try to create any additional polygon or layer with new polygons, I get an error message saying there are duplicate nodes.

Searching online, there is a lack of useful information or guidance to explain what is going wrong.

What is going wrong?

enter image description here

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When I try to create any additional polygon or layer with new polygons, I get an error message saying there are duplicate nodes.

You get this error if you try to close the polygon by doing a double left click. You must do a right click.

If you want to draw a triangle, you do 3 left clicks then a right click to finish it.

  • Hi JGH, Thank you for your advice. I did a right click once to close up the polygon which is the orange rectangle on the "store" layer as per the image attachment. When my mouse pointer goes past the rectangle, a point closest to the mouse pointer lights up on the polygon. I try to click the Add Feature icon and the mouse pointer changes to a crosshair. However, no points are created on clicking the map. I then get the error message "Add feature: ring 0 with less than four points Geometry has 1 errors. Validation finished" upon further clicking on the map. Any insight is much appreciated. – ian Feb 22 '18 at 3:22

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