Another Example of GeoPandas and Python Spatial Joins

Another Example of GeoPandas and Python Spatial Joins

Yesterday, I posted a much more complicated piece of code that pulled addresses from the SAM (State Address Management) database and did a spatial join to add a column to the file with Assembly District and Municipality. This was a bit too complex, so I made a simpler one for other purposes that doesn’t require the coordinates to be obtained from SAM.

This python script takes two parameters:

• Path to a CSV file that contains an X and Y coordinate
• Path to a Shapefile or Geopackage to Join Against

Then the code will create a new CSV file with the spatially joined attributes pulled from the Shapefile. I have only run it on a few large data sets, but I found it took roughly 1 second to join 1,000 records from call to end of end of script.

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#!/usr/bin/python
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import requests,sys,json,os,csv
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import pandas as pd
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import geopandas as gpd
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lines=[]
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# read list of addresses from parameter 1
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with open(sys.argv[-2], newline='') as csvfile: 
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    for line in csv.DictReader(csvfile):
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        lines.append(line)
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# convert to pandas
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locPd = pd.DataFrame(lines,columns=lines[0].keys())
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locPd.convert_dtypes()
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locPd = gpd.GeoDataFrame(locPd,  geometry=gpd.points_from_xy(locPd.x.astype('float32'), locPd.y.astype('float32')))
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# run spatial joins against parameter 2
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ad = gpd.read_file(sys.argv[-1])
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locPd = gpd.sjoin(locPd, ad, op="within")
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# remove added geometery and index columns
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del locPd['geometry']
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del locPd['index_right']
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# write pandas back to out csv
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locPd.to_csv (os.path.splitext(sys.argv[-2])[0]+'-output.csv', index = False, header=True)