GeoPandas Set CRS on Points

Question

Given the following GeoDataFrame:

h=pd.DataFrame({'zip':[19152,19047],
               'Lat':[40.058841,40.202162],
               'Lon':[-75.042164,-74.924594]})
crs='none'
geometry = [Point(xy) for xy in zip(h.Lon, h.Lat)]
hg = GeoDataFrame(h, crs=crs, geometry=geometry)
hg

       Lat          Lon     zip     geometry
0   40.058841   -75.042164  19152   POINT (-75.042164 40.058841)
1   40.202162   -74.924594  19047   POINT (-74.924594 40.202162)

I need to set the CRS as I did with another GeoDataFrame (like this):

c=c.to_crs("+init=epsg:3857 +ellps=GRS80 +datum=GGRS87 +units=mi +no_defs")

I've tried this:

crs={'init': 'epsg:3857'}

and this:

hg=hg.to_crs("+init=epsg:3857 +ellps=GRS80 +datum=GGRS87 +units=mi +no_defs")

...but no luck.

Some important notes:

The other GeoDataFrame for which the above .to_crs method worked was from a shape file and the geometry column was for polygons, not points. Its 'geometry' values looked like this after the .to_crs method was applied:

POLYGON ((-5973.005380655156 3399.646267693398... and when I try the above with the hg GeoDataFrame, they still look like regular lat/long coordinates.
If/when this works out, I'll then concatenate these points with the polygon GeoDataFrame in order to plot both (points on top of polygons).
When I try concatenating the GeoDataFrames first before using the .to_crs method, and then I use the method on both the point and polygon rows at once, I get the following error:

ValueError: Cannot transform naive geometries. Please set a crs on the object first.

Thanks in advance!

Ufos · Accepted Answer · 2021-02-01T13:27:42.730

69

Geopandas API got cleaned up, and now works without surprises. Make sure to use the lastest stable version and read the docs.

Setting the CRS on a GeoDataFrame using its EPSG code is as simple as

gdf.set_crs(epsg=4326, inplace=True)

where gdf is a geopandas.geodataframe.GeoDataFrame. Watch out for the explicit inplace!

So in the example above it would be:

import pandas as pd
from shapely.geometry import Point
from geopandas import GeoDataFrame

df = pd.DataFrame({'zip':[19152,19047],
               'Lat':[40.058841,40.202162],
               'Lon':[-75.042164,-74.924594]})

geometry = [Point(xy) for xy in zip(df.Lon, df.Lat)]
gdf = GeoDataFrame(df, geometry=geometry)

gdf.set_crs(epsg=4326, inplace=True)
# ^ comment out to get a "Cannot transform naive geometries" error below

# project to merkator
gdf.to_crs(epsg=3395)

     zip        Lat        Lon                          geometry
0  19152  40.058841 -75.042164  POINT (-8353655.485 4846992.030)
1  19047  40.202162 -74.924594  POINT (-8340567.652 4867777.107)

edited Feb 01 '21 at 13:27

answered Aug 30 '18 at 18:02

Ufos

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`GeoDataFrame(df, geometry=geometry, crs='EPSG:4326')` would also work – Ufos Oct 28 '20 at 23:34
@JanPisl, it does work on the latest stable version of geopandas (`0.8.2`). What do you mean by "no longer valid"? What version of python and geopandas are you using? – Ufos Feb 01 '21 at 13:31
1

Ok sorry my bad! I use 0.7. Let me correct myself: If you get *** AttributeError: 'GeoDataFrame' object has no attribute 'set_crs' , try answer from shyam – Jan Pisl Feb 01 '21 at 14:13
any way only with shapely ? – Cristián Vargas Acevedo Aug 04 '21 at 13:51

score 14 · Answer 2 · answered May 27 '20 at 13:03

14

The format for Setting CRS in GeoPandas is now

gdf.crs = "EPSG:4326"

The earlier format is deprecated

ref: https://geopandas.org/projections.html

answered May 27 '20 at 13:03

shyam

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in such cases it's better to suggest and edit to an already accepted answer, or, at least, leave a comment. I've updated my answer, changes should go live once someone gets to review them. – Ufos Sep 28 '20 at 17:00

score 2 · Answer 3 · edited Nov 29 '18 at 11:41

2

The answer was here all along:

hg=hg.to_crs(c.crs)

This sets the crs for hg to that of c.

edited Nov 29 '18 at 11:41

Denis Gordeev

454
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answered Aug 15 '16 at 20:47

Dance Party2

7,214
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The answer is also wrong. `to_crs` transforms from one CRS to another, while `.crs = {...}` sets the initial crs. – Ufos Aug 30 '18 at 18:03
@Ufos you say "also", are you suggesting that all answers in this thread are incorrect? – baxx Feb 22 '20 at 15:56
@baxx my other comment got removed as the link in the answer was fixed. The comment was "the link is dead". So, now "also" does not make sense, but I cannot edit the comment. – Ufos Feb 26 '20 at 18:47
1

If you check the for-now-working link, you will see that there `to_crs` is used to transform the coordinates, not to set the CRS. – Ufos Feb 26 '20 at 18:50

GeoPandas Set CRS on Points

3 Answers3

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