Hi everyone,
I’m experiencing projection errors following a groupby on geodataframe. Below you will find the libraries that I am using:
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import matplotlib
import holoviews as hv
from holoviews import opts
import panel as pn
from bokeh.resources import INLINE
import geopandas as gpd
import geoviews as gv
from cartopy import crs
hv.extension('bokeh', 'matplotlib')
gv.extension('bokeh')
pd.options.plotting.backend = 'holoviews'
Whilst these are the versions of some key libraries:
bokeh 2.1.1
geopandas 0.6.1
geoviews 1.8.1
holoviews 1.13.3
I have concatenated 3 shapefiles to build a polygon picture of UK healthcare boundaries (links to files provided if needed). Unfortunately, from what i have found the UK doesn’t produce one file that combines all of those, so have had to merge the shape files from the 3 individual countries i’m interested in. The 3 shape files have a size of:
shape file 1 = (https://www.opendatani.gov.uk/dataset/department-of-health-trust-boundaries)
shape file 2 = (https://geoportal.statistics.gov.uk/datasets/5252644ec26e4bffadf9d3661eef4826_4)
shape file 3 = I’m a new user so I can’t post the 3rd link, sorry! But it is the Welsh CCG boundries
My code to concat them together is below:
England_CCG.drop(['objectid', 'bng_e', 'bng_n', 'long', 'lat', 'st_areasha', 'st_lengths'], inplace = True, axis = 1 )
Wales_HB.drop(['objectid', 'bng_e', 'bng_n', 'long', 'lat', 'st_areasha', 'st_lengths', 'lhb16nmw'], inplace = True, axis = 1 )
Scotland_HB.drop(['Shape_Leng', 'Shape_Area'], inplace = True, axis = 1)
#NI_HB.drop(['Shape_Leng', 'Shape_Area'], inplace = True, axis = 1 )
England_CCG.rename(columns={'ccg20cd': 'CCG_Code', 'ccg20nm': 'CCG_Name'}, inplace = True )
Wales_HB.rename(columns={'lhb16cd': 'CCG_Code', 'lhb16nm': 'CCG_Name'}, inplace = True )
Scotland_HB.rename(columns={'HBCode': 'CCG_Code', 'HBName': 'CCG_Name'}, inplace = True )
#NI_HB.rename(columns={'TrustCode': 'CCG_Code', 'TrustName': 'CCG_Name'}, inplace = True )
UK_shape = [England_CCG, Wales_HB, Scotland_HB]
Merged_Shapes = gpd.GeoDataFrame(pd.concat(UK_shape))
Each of the files has the same esri projection once joined, and the shape plots perfectly as one when I run:
Test= gv.Polygons(Merged_Shapes, vdims=[('CCG_Name')], crs=crs.OSGB())
This gives me a polygon plot of the UK, with all the area boundaries for each ccg.
To my geodataframe, I then add a new column, called ‘Country’ which attributes each CCG to whatever the country they belong to. So, all the Welsh CCGs are attributed to Wales, all the English ones to England and all the Scottish ones to Scotland.
What I want to achieve is to have a dropdown next to the polygon map I am making, that will show all the CCGs in a particular country when it is selected from the drop down widget. I understand that one to to do this is by a groupby. However, when I use the following code to achieve this:
c1 = gv.Polygons(Merged_Shapes, vdims=[('CCG_Name','Country')], crs=crs.OSGB()).groupby(['Country'])
I get a long list of projection errors stating:
“WARNING:param.project_path: While projecting a Polygons element from a PlateCarree coordinate reference system (crs) to a Mercator projection none of the projected paths were contained within the bounds specified by the projection. Ensure you have specified the correct coordinate system for your data.”
To which I am left without a map but I retain the widget. Does anyone know what is going wrong here and what a possible solution would be? its been driving me crazy!
Kind regards,