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To do some geospatial analysis I am using the USA counties map from topojson/us-atlas repository

After loading the link https://cdn.jsdelivr.net/npm/us-atlas@3/counties-10m.json in geopandas I get the geodataframe correctly.

import geopandas as gpd
counties = gpd.read_file('https://cdn.jsdelivr.net/npm/us-atlas@3/counties-10m.json')

Then I just do the following to get the longitude and latitude -

counties['lon'] = counties['geometry'].centroid.x
counties['lat'] = counties['geometry'].centroid.y

But I get the error -

IndexError: list index out of range

Only the centroid attribute seems to give the output :
counties['geometry'].centroid gives -

0       POINT (-113.75823 35.70499)
1        POINT (-90.40498 30.62627)
2       POINT (-114.13825 43.00235)
3        POINT (-96.40159 47.77421)
4        POINT (-97.24835 46.93312)

Any idea how to get the longitude and latitude of the counties / states from the us-atlas file?

  • Is it possible that you have missing geometry somewhere? Or invalid? That could cause the error. – martinfleis Oct 28 at 9:15
  • @martinfleis Ummm....but if i had missing geometry then calling just centroid too would have given error right? I plotted the raw data and it worked, so I figured that atleast the geometries are alright. But I not so sure. Maybe you can check since the file is there in topojson's repository. – jar Oct 28 at 9:23
  • No, centroid gives None in that case. You can check with counties.geometry.isna().any(), counties.geometry.is_empty().any() and counties.geometry.is_valid().any(). – martinfleis Oct 28 at 9:27
  • I see. When I tried counties.geometry.isna().any() I get False. But the rest give the same error TypeError: 'Series' object is not callable – jar Oct 28 at 9:44
  • Of sorry, those are properties, so without (). As counties.geometry.is_empty.any() – martinfleis Oct 28 at 10:12
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You get IndexError of this kind if the GeoSeries with centroid does contain empty geometry.

You have to check if all geometries are valid and non-empty.

counties.geometry.is_empty.any()

counties.geometry.is_valid.any()

If you get True for any of those, you will have to drop affected rows. On of the options is below.

empty = counties.geometry.is_empty

counties_non_empty = counties[~empty]

counties_non_empty['lon'] = counties_non_empty['geometry'].centroid.x
counties_non_empty['lat'] = counties_non_empty['geometry'].centroid.y
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