Merging/Dissolving polygons by Common Attribute Field in QGIS?

Question

I have joined corresponding Local Enterprise Partnerships table data into a polygon shapefile containing UK Local Authorities.

How do I Dissolve or Merge the the Local Authorities polygons by LEP_NAME as shown in the screenshot?

Ideally, I would like to retain the Local Authority attributes with the resultant merged polygons. I have zero scripting knowledge so am looking for a tool based solution. Any help or pointers much appreciated.

Additional Note: When attempting to use the dissolve tool the LEP_NAME field is not available as shown above. The LEP attribute data was created in Excel, saved as CSV format and joined to the Local Authority polygon shapefile. There are duplicate IDENTIFI0 fields as shown in the other screenshot - could this be the root of the issue?

Kurt · Answer

use vector ->geoprocessing tools --> dissolve:

select  shapefile and field (LEP_NAME in your case), choose name for new shapefile  and you are done

abarrington · Answer

I had the same issue. I solved it by saving the post-join shape file down and then dissolving after that. Make sure you have the correct vector layer selected in the dissolve prompt to get your new fields.

Answered by abarrington on May 1, 2021

Cuitlahuac Hernandez-Santiago · Answer

regarding this issue I found that fields does not appears in the drop-down menu when the field "type" is float.

It varies according to the software used, but copying the values to a text field may usually work.

Hope this helps to somebody else.

CalebJ · Answer

When one creates a join and links an existing shapefile attribute table with another table, do export the two joined table as a new shapefile and load it again into QGIS. The joined table's fields will then be accessible to various QGIS tools, e.g., dissolve.

Answered by CalebJ on May 1, 2021

Merging/Dissolving polygons by Common Attribute Field in QGIS?

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