Dissolving not based on attribute in GeoPandas

Question

I would like to dissolve a shapefile regardless of attribute content using geopandas. The regular dissolve can be accomplished with something like this:

import geopandas

all = geopandas.read_file(r'Inputs\All.shp')    
all = all.dissolve(by='topology')    
all.to_file(driver='ESRI Shapefile', filename=r'Intermediate\All_dissolved.shp')

But the above is using the 'topology' field to aggregate. I have also noticed that the all.dissolve() function exits with an error, indicating that the by parameter is required.

How can I dissolve regardless of the attribute in GeoPandas?

Answer 1

You will lose all attributes but unary_union will return one big multipolygon which you can turn into singleparts with .geoms:

import geopandas as gpd
df = gpd.read_file(r"C:\Test\New_Shapefile.shp")
df.plot(cmap='cool')

df2 = gpd.geoseries.GeoSeries([geom for geom in df.unary_union.geoms])
df2.plot(cmap='cool')

(You can also add a column, fill with some value and then dissolve by

df['dissolvefield'] = 1
df2 = df.dissolve(by='dissolvefield')
df3 = gpd.geoseries.GeoSeries([geom for geom in df2.geometry.iloc[0].geoms])

)