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I'm having a bit of trouble changing the CRS in a GeoDataFrame created by iterating over a larger dataset. The epsg is set to the correct value (5070, an Albers Equal Area projection using meters) but when plotting the data GeoPandas uses the wrong CRS. I'm relatively new to GeoPandas and python, so the problem might be very simple. Thanks for taking a look!

import geopandas as gpd
from geopandas import GeoDataFrame
import matplotlib.pyplot as plt

counties = gpd.read_file("C:/Users/j62/Documents/Practice Data/cb_2018_us_county_5m (1)")

contus = GeoDataFrame(columns=counties.columns)
for index, row in counties.iterrows():
  if (int(row['STATEFP']) <= 56) & (int(row['STATEFP']) != 2) & (int(row['STATEFP']) != 15):
    contus.loc[index,:] = row

contus.set_crs(epsg=5070,inplace=True)
print(contus.crs)
contus.plot()

This outputs epsg:5070 from the print statement and a map showing the data in a geographic coordinate system using lat/lon.

I've tried setting the CRS in the original GDF, which does seem to work correctly, but I'm unable to alter it afterword in the 'contus' GDF.

James
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1 Answers1

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To change the crs of the contus GeoDataframe, it will work to assign the output of the method to a new GeoDataframe:

contus = contus.set_crs(epsg=5070)
contus.plot()

I prefer to do spatial calculations (intersect, buffer) in CRS:5070, Albers Equal Area, and then reproject back into CRS:4326 for export and mapping.

eKerney
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