[GIS] Merging multiple vector layers to one layer with multiple geom types with QGIS

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I have a situation where I need to merge a large number of spatial files into a single output with a free tool like QGIS, rather than FME or Alteryx.

Along the lines of this post:
Merging multiple vector layers to one layer using QGIS?

However, I have some point features, some line features, and some polygon features. This rules out outputs like shapefiles, but anything else is fine like GML, TAB, or a database.

Is there anyway to do this in QGIS?

Every process or model I try makes a shapefile at some point which means this can't work.

Best Answer

You can merge layers with different geometry types together with ogr2ogr.

Here is an example about merging an point shapefile and polygon shapefile into GeoPackage as a new layer "merged" that has a generic geometry type.

ogr2ogr -f gpkg merged.gpkg point.shp -nln merged -nlt geometry
ogr2ogr -f gpkg -update -append merged.gpkg polygon.shp -nln merged -nlt geometry

ogrinfo merged.gpkg merged
INFO: Open of `merged.gpkg'
      using driver `GPKG' successful.

Layer name: merged
Metadata:
  DBF_DATE_LAST_UPDATE=2017-03-31
Geometry: Unknown (any)
Feature Count: 2
Extent: (309.000000, 478.000000) - (599.000000, 604.000000)
Layer SRS WKT:
(unknown)
FID Column = fid
Geometry Column = geom
attr: String (1.0)
OGRFeature(merged):1
  attr (String) = B
  POINT (382 478)

OGRFeature(merged):2
  attr (String) = A
  POLYGON ((309 584,599 604,466 493,309 584))

However, you will have some problems with QGIS with using that layer because QGIS can't handle points, lines, and polygons on a same layer. QGIS requires that layer is split by the geometry type

You can open the merged layer as a single layer with OpenJUMP.

Related Solutions

QGIS Merge – How to Merge Multiple Vector Layers to One Layer Using QGIS

You can use MMQGIS tools for merging...

mmqgis

The merge layers tool merges features from multiple layers into a single shapefile and adds the merged shapefile to the project. One or more layers are selected from the "Select Source Layers" dialog list box and an output shapefile name is specified in the "Output Shapefile" dialog field.

Merged layers must all be the same geometry type (point, polygon, etc.). If the source layers have different attribute fields (distinguished by name and type), the merged file will contain a set of all different fields from the source layers with NULL values inserted when a source layer does not have a specific output field.

i hope it helps you...

QGIS – How to Use ‘Merge Vector Layers’ with Geopackages as Output

As long as the QGIS fix is not ready you can use ogr2ogr for merging the layers. Use it with parameter -unsetFid https://www.gdal.org/ogr2ogr.html. Run this command for all your input layers for appending data from the layers to a single table named "merged"

ogr2ogr -f gpkg -update -append -unsetFid output.gpkg input_layer1 -nln merged

Afterward of @ndawson's comment and @user30184's answer. I wrote a batch file for Windows that iterates in all OUTPUTS with the pattern iterate_*.gpkg and merges all in one file this way:

echo off set dst_datasource_name=voronoi_merge.gpkg del %dst_datasource_name% for %%f in (iterate_*.gpkg) do ( echo Merging %%~nf ogr2ogr -f gpkg -update -append -unsetFid %dst_datasource_name% %%~nf.gpkg -nln voronoi_merge )

This file must be run from the folder with all the OUTPUTS

Best Answer

Related Solutions

QGIS Merge – How to Merge Multiple Vector Layers to One Layer Using QGIS

QGIS – How to Use ‘Merge Vector Layers’ with Geopackages as Output

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