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I have nearly a thousand layers of geospatial data consisting only of Point layers and Line Layers and I just want to make it so that I only have one layer for each type.

Is there a way to filter to only run the Data Management Tools > Merge Vector Layers on just one type of layer at a time (e.g. Points only first and then Layer)?

Or at least on how to load only one of them at a time into QGIS? The data is from a (single) KMZ file.

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  • Only load the line layers and merge them, then do the same for the points. tada.
    – Erik
    Sep 8, 2021 at 7:50
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    @Erik, I can't. those layers are already stored as one KMZ/KML file. I have updated my question to be more clear Sep 8, 2021 at 7:52
  • You simply could remove the layers of the type you don't need, then.
    – Erik
    Sep 8, 2021 at 8:12
  • 1
    @Erik with hundreds of layers it's going to be very cumbersome. So better reload to file and select there the geometry type.
    – Babel
    Sep 8, 2021 at 8:15

2 Answers 2

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You can use PyQGIS:

layerlist = []
for lyr in QgsProject().instance().mapLayers().values(): #For every layer added to the map
    if lyr.geometryType()==1: #1 is line, 2 polygon, 0 point
        layerlist.append(lyr) #If the geometrytype is 1, then append the layer to layerlist

processing.runAndLoadResults("native:mergevectorlayers", {'LAYERS':layerlist,'CRS':None,'OUTPUT':'TEMPORARY_OUTPUT'})

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And if you want to you can automate the merging by grouping the geometry types using collections.defaultdict(list):

from collections import defaultdict as dd

list_them = dd(list)

numtoname = {0:'points', 1:'lines', 2:'polygons'}
for lyr in QgsProject().instance().mapLayers().values():
    list_them[numtoname[lyr.geometryType()]].append(lyr)
    
for geomtype, layerlist in list_them.items():
    print(geomtype)
    print(layerlist)
    processing.runAndLoadResults("native:mergevectorlayers", {'LAYERS':layerlist,'CRS':None,'OUTPUT':'TEMPORARY_OUTPUT'})

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0
4

When you create a new, empty project and you load the kmz file, you can choose to load only point- or only line layers. Select one of them and do processing separately.

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