reduce the precision of geometries in a Pandas GeoDataFrame

round_gpd_geoms.py

#when saving GeoDataFrames as csv, high precision geometries can produce large files on disk
#reducing unnecessary precision can help reduce file size
#e.g. ONS digital vector boundary data converted from shp to gpd results in nano-metre precision!

import geopandas as gpd
from shapely.wkt import loads
from shapely.wkt import dumps

#set desired number of decimal places (e.g. see https://xkcd.com/2170/) 
precision = 0

simple = not_simple.copy(deep=False)  #not_simple is a Pandas GeoDataFrame (with geometries in 'geometry' column)

#with help from https://gis.stackexchange.com/a/336382
simple.geometry = not_simple.geometry.apply(lambda x: loads(dumps(x,rounding_precision=precision)))

#to remove dps entirely (truncate), run next line after last line using precsion=0
#e.g. useful when working with British National Grid CRS (units metres) 
trunc.geometry = simple.geometry.apply(lambda x: loads(dumps(x,trim=True)))

#then write
trunc.to_csv(not_simple_truncated.csv)