How to visualize data on a map using Python

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Stratos Matzouranis

The journey began in 2008 where I officially started working in the field of IT (IT). Starting the first semester of school I realized a special attraction towards databases and automation. I have been involved with databases such as Microsoft SQL Server / Oracle Database, data analysis and automations using the command line (CLI), Visual Basic for Applications and Python. Through years of experience I have developed these capabilities so that I can make my life easier. For me, the purpose of every IT guy and every office worker is to have the knowledge so that through tools he can work a little but produce a lot. Through this his website DataPlatform.gr I try to offer knowledge and propose solutions to everyday problems.

Certifications:

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In this article with his help jupyter notebook and her python we will make one heatmap. We will do a full analysis using dataframe, polynomial regression scatter plot, bar plot.

Let's start by loading the libraries we'll need:

import folium  #είναι για την δημιουργία χάρτη
import json
import numpy as np  #easy maths calculations
import pandas as pd    #για τα dataframe
import matplotlib      #για τα γραφήματα
import matplotlib.pyplot as plt

geo_Data = 'https://raw.githubusercontent.com/python-visualization/folium/master/examples/data/world-countries.json'

But what is the json we put in the geo_Data variable?

It is essentially a file with associated countries with their coordinates that is needed in the folium to make the margins of the map.

In the next step we will load a csv with data I found for Europe and they make us for example:

dfun = pd.read_csv('https://gist.githubusercontent.com/str4t3gos/d089dd9bab5d075a4c39e48da301b374/raw/653feea057e6b7aa54ee772922e696e7f7d1ba61/country_un2.csv')

After we have loaded into a variable that has taken the properties of the panda dataframe as csv with the command .head() show us our data:

dfun.head()

We can filter the data of the dataframe, for example bring only the data of 2017:

dfun17 = dfun[dfun['YEAR'] == 2017]

dfun17.head()

Let's fill another variable with the 2010 data, we'll need it later:

dfun10 = dfun[dfun['YEAR'] == 2010]

dfun10.head()

We set the map properties from folium to a variable and put the colors to it along with the rest of the arguments via the choropleth property.

*Let me remind you that legend is the box that explains what the different colors we see mean. Also with the .save property we have the possibility to save it as html.

Create a map

sf_map= folium.Map([40., 10.], zoom_start=4)

sf_map.choropleth(

    geo_data=geo_Data,

    name='choropleth',

    data=dfun17,

    columns=['COUNTRY','VALUE'],

    fill_color='BuPu',

    fill_opacity=0.7,

    line_opacity=0.5,

    key_on='feature.properties.name',

    legend_name='Unemployment Rate (%)'

)

folium.LayerControl().add_to(sf_map)

sf_map

#sf_map.save('europe17.html')

Let's see the difference with 2010 when we made the other dataframe:

sf_map10= folium.Map([40., 10.], zoom_start=4)

sf_map10.choropleth(

    geo_data=geo_Data,

    name='choropleth',

    data=dfun10,

    columns=['COUNTRY','VALUE'],

    fill_color='BuPu',

    fill_opacity=0.7,

    line_opacity=0.5,

    key_on='feature.properties.name',

    legend_name='Unemployment Rate (%)'

)

folium.LayerControl().add_to(sf_map10)

sf_map10

Create a polynomial regression graph

Let's make a polynomial regression graph with the data of each year of Greece.

We will need a new dataframe filtered only with Greece and to import the seaborn library:

dgreece = dfun[dfun['COUNTRY'] == 'Greece']

dgreecefinal = dgreece[['YEAR','VALUE']]

import seaborn as sns

ax = sns.regplot(x="YEAR", y="VALUE", data=dgreecefinal,

                 scatter_kws={"s": 80},

                 order=6, ci=None)

Create a bar plot graph

Let's go to the last example.

We will make a barplot graph with the data of Greece from 2007 onwards:

dgreecefinal10years = dgreecefinal[dgreecefinal['YEAR'] >=2007]

dgreecefinal10years.head()

We will use the matplotlib library by setting its parameter and with the .show property it makes the display:

%matplotlib inline

ax=dgreecefinal10years.plot.bar('YEAR','VALUE')

ax.spines['left'].set_visible(False)

ax.spines['top'].set_visible(False)

ax.spines['right'].set_visible(False)

for p in ax.patches:

    ax.annotate(np.round(p.get_height(),decimals=2), 

                (p.get_x()+p.get_width()/2., p.get_height()), 

                ha='center', 

                va='center', 

                xytext=(0, 10), 

                textcoords='offset points',

                fontsize = 12

               )

ax.legend(['Greece'],loc='upper left')

plt.show()

Sources:

• Folium