I want to merge multiple buffer file to already available shapefile but I'm not sure how to do it. I already applied vector->Data management tools->Merge vector layers, but this is not giving me the actual answer I was expected.

Here is a screen shot of the result I got it after merging multiple buffer files: -

enter image description here

But, I want the result in one shapefile like this: -

enter image description here

Is there any solution using QGIS?

  • try vector > geoprocessing tools > union – firefly-orange Mar 7 '18 at 13:50
  • @firefly-orange, it is giving me the same result as it is mentioned above in image (1) without the buffer area. But i need to make the same shape file as image (2). Any further idea? – Ahsan Nawaz Mar 7 '18 at 14:01
  • To me it seems your added buffer shapes are hiding original country outline, being placed on top of the original shapefile. To control the order, open Layer Properties | Style and tick the checkbox on Control feature rendering order and set Define order (small A-Z icon). You will need a field in which you can set numbers (e.g. 1, 2,...) which can be used for sorting. – Kazuhito Mar 7 '18 at 14:38
  • It may not be easy to add a field and populate the value (1, 2, 3...) manually for all features. You may as well set an expression, for instance $area and set the order Descending. It brings smaller polygon to the front. Not sure if this works well for your dataset, though. – Kazuhito Mar 7 '18 at 14:54
  • @Kazuhito, No this solution is not working in my case. It gives a wage image. Any other solution? – Ahsan Nawaz Mar 7 '18 at 15:46

I faced with this problem.

First of all you should be sure that layers for merging must save in the same projection. Then to merge layers you have to use Qgis plugin Merge Shapes. It more flexible and correct working than «vector->Data management tools->Merge vector layers».


Control rendering order to visualize overlapping polygons

Step 1: Add a new field to your mergeShapeFile.

  • Field Name: order
  • Field Type: whole number
  • Length: 2

enter image description here

Step 2: Select all the polygons you want in the top layer, in this case your country polygons. Fill in the value 1 in the order field.

enter image description here

Select all the polygons you want in the lower layer, in this case the buffer polygons. Fill in the value 0 in the order field.

Step 3: Layer Properties > Style > check box next to "Control feature rendering order." Select "order" as the field to control rendering order.

enter image description here

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