Brazilian Election Data Analysis

Welcome! This repo was created to upload our data analisys project.

📝 Project Summary

This project had the intention of covering all steps of an ELT data integration, from extraction, passing through a creation of a data lake, uploaded to a database (data warehouse) and being transformed for data visualization.

Step 1: Data Acquisition

The data was acquired through the TSE (Brazilian Superior Electoral Court) repository.

To do so, it was used scrapy library to create a crawler that look up for HTML tags and download the correspondent files.

file_url = response.css('.resource-url-analytics::attr(href)').get()

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Step 2: Handling Data

Using the following Python libraries:

import os
import csv 
import pandas
import random
import zipfile
import pathlib
import sqlalchemy

The data was handled in a way to minimize and optmize memory and storage, so the steps were the following:

• Extracting file
• Deleting original zip file
• Creating a list with files path
• Creating and uploading table to postgreSQL

It was used only a 10% sample of the data, chosen randomly.

💡 Tip: If you want to use the totality of the datasets, then you should use copy_table function combined with pandas .head method. Once COPY TABLE statement require less memory usage.

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Step 3: PostgreSQL 🐘 and Dremio🐬 with Docker 🐳

Docker was used to easy the applications setup by creating containers as shown on the diagram:

PostgreSQL was chosen for its open source characteristics and easy conection to Dremio.

And lastly Dremio was used as a mid man between PostgreSQL and PowerBI because of its PowerBI integration and interactive analytics directly on the data lake.

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Step 4: Setting up Dremio's Virtual Datesets

Dremio was mainly used to create virtual datasets, known as views in a SQL database. A series of SQL queries were made to format data type, remove the missing values from the data source and direct connecting those views to PowerBI.

Select 
    Cast(Replace("ANO_ELEICAO", '"', '') AS varchar(100)) AS "ANO_ELEICAO",
    Cast(Replace("SG_UF", '"', '') AS varchar(100)) AS "SG_UF",
    Cast(Replace("CD_MUNICIPIO", '"', '') AS varchar(100)) AS "CD_MUNICIPIO",
    Cast(Replace("NM_MUNICIPIO", '"', '') AS varchar(100)) AS "NM_MUNICIPIO",
    Cast(Replace("CD_GENERO", '"', '') AS varchar(100)) AS "CD_GENERO",
    Cast(Replace("DS_GENERO", '"', '') AS varchar(100)) AS "DS_GENERO",
    Cast(Replace("QT_ELEITORES_PERFIL", '"', '') AS bigint) AS "QT_ELEITORES_PERFIL",
    Cast(Replace("QT_ELEITORES_BIOMETRIA", '"', '') AS bigint) AS "QT_ELEITORES_BIOMETRIA",
    Cast(Replace("QT_ELEITORES_DEFICIENCIA", '"', '') AS bigint) AS "QT_ELEITORES_DEFICIENCIA",
    Cast(Replace("QT_ELEITORES_INC_NM_SOCIAL", '"', '') AS bigint) AS "QT_ELEITORES_INC_NM_SOCIAL"
From "perfil_eleitorado_1994.csv"

Prior to the formatting queries, a verification of the columns was done:

Select 
CASE 
WHEN (Select COUNT("CD_MUN_SIT_BIOMETRICA") 
        FROM "perfil_eleitorado_1994.csv"
        Where "CD_MUN_SIT_BIOMETRICA" = '-3') = COUNT("CD_MUN_SIT_BIOMETRICA") THEN TRUE
ELSE FALSE
END AS "CD_MUN_SIT_BIOMETRICA", 
CASE
WHEN (Select COUNT("NR_ZONA") 
        FROM "perfil_eleitorado_1994.csv"
        Where "NR_ZONA" = '-1') = COUNT("NR_ZONA") THEN TRUE
ELSE FALSE
END AS "NR_ZONA",
CASE
WHEN (Select COUNT("CD_ESTADO_CIVIL") 
        FROM "perfil_eleitorado_1994.csv"
        Where "CD_ESTADO_CIVIL" = '-3') = COUNT("CD_ESTADO_CIVIL") THEN TRUE
ELSE FALSE
END AS "CD_ESTADO_CIVIL",
CASE
WHEN (Select COUNT("CD_FAIXA_ETARIA") 
        FROM "perfil_eleitorado_1994.csv"
        Where "CD_FAIXA_ETARIA" = '-3') = COUNT("CD_FAIXA_ETARIA") THEN TRUE 
ELSE FALSE
END AS "CD_FAIXA_ETARIA",
CASE
WHEN (Select COUNT("CD_GRAU_ESCOLARIDADE") 
        FROM "perfil_eleitorado_1994.csv"
        Where "CD_GRAU_ESCOLARIDADE" = '0') = COUNT("CD_GRAU_ESCOLARIDADE") THEN TRUE
ELSE FALSE 
END AS "CD_GRAU_ESCOLARIDADE"
FROM "perfil_eleitorado_1994.csv"

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Step 5: Data Visualization with PowerBI

PowerBI is a widely used collection of software services, easy to use and with a self-service approach to Business Inteligence. The data visualization of this project was made with PowerBI.

As an example the following images are some of the graphics created with PowerBI

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⬇️ If you want to access the full project file you can download it here