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I use MMQgis plugin to create buffers around points. Some of them overlapping and, to my analysis, i have to "dissolve" lines that cross this buffers. I use Vector -> Geoprocess -> Dissolve, and it was similar to what I wanted, if it were not for the fact that all attribute values have become just one!

Attribute table before dissolve: enter image description here

Features after dissolve: enter image description here

Table after dissolve: enter image description here

How should I to proceed?

PolyGeo
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Abilio André
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1 Answers1

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You might be able to do it with the following workflow:

  1. First do the dissolve like you've done, which results in one multi-polygon
  2. Now split them out using the 'vector' -> 'geometry tools' -> 'multipart to singleparts' operator singlepart to multipart
  3. Now do a spatial join with 'vector' -> 'data management tools' -> 'join attributes by location' to get your attributes back. spatial join

Edit:

For the join by location, you should either use your original points to join to the 'singlepart' features (with a contains operation) or use your buffers (using intersects). You'll only be able to copy attributes from one of the features, where two or more have been merged, of course.

Alex Leith
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  • Thank you ALex Leith! But I still need help ... what are the layers involved in the process of putting attributes together by location?

    The resulting buffer after the "multipart to single part" - a.k.a MS - was used to "Join attributes by location" with the original buffers (which contains all the information). Did not work. The resulting shape now has 6 polygons (result of dissolve), but all information is the same ... similar to MS.

     – Abilio André Jan 18 '18 at 13:59
  • Hey @AbilioAndré, the join by location should be either your original points (with contains) or your buffers (using intersects). You'll only be able to copy attributes from one of the features, where two or more have been merged, of course. – Alex Leith Jan 18 '18 at 22:20