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Building a scatter plot for Untappd Breweries

Время чтения текста – 7 минут

Today we are going to build a scatter plot for Russian Breweries that would display the ratio between the number of reviews and their average ratings for the past 30 days. Data will be taken from check-ins left by Untappd users who rated beers. To make a plot we need markers with specified color and size. The color will depend on a brewery registration date, thus displaying it’s registration period on Untappd, while the size of a marker correlates with the range of beers represented. This article is the first part of our series dedicated to building dashboards with Plotly.

Writing a Clickhouse query

First, we need to process the data before using it in our dashboard. Here, we are using public data collected from Untappd. You can find more about this in our previous articles: Handling website buttons in Selenium and Example of using dictionaries in Clickhouse with Untappd.

from datetime import datetime, timedelta
from clickhouse_driver import Client
import plotly.graph_objects as go
import pandas as pd
import numpy as np
client = Client(host='ec1-2-34-567-89.us-east-2.compute.amazonaws.com', user='default', password='', port='9000', database='default')

Our scatter plot will depend on the  get_scatter_plot(n_days, top_n) function, which takes two arguments denoting a time span and a number of breweries to display. Let’s write a SQL query to calculate the Brewery Pure Average. It can be presented the following: multiply the beer rating by the total number of ratings and divide it by the number of brewery reviews. We will also pass a brewery name and its beer range to the query, these parameters can be fetched from our dictionary using the  dictGet function. We are only interested in those breweries that have Brewery Pure Average > 0 and the number of reviews > 100.

brewery_pure_average = client.execute(f"""
SELECT
       t1.brewery_id,
       sum(t1.beer_pure_average_mult_count / t2.count_for_that_brewery) AS brewery_pure_average,
       t2.count_for_that_brewery,
       dictGet('breweries', 'brewery_name', toUInt64(t1.brewery_id)),
       dictGet('breweries', 'beer_count', toUInt64(t1.brewery_id)),
       t3.stats_age_on_service / 365
   FROM
   (
       SELECT
           beer_id,
           brewery_id,
           sum(rating_score) AS beer_pure_average_mult_count
       FROM beer_reviews
       WHERE created_at >= today()-{n_days}
       GROUP BY
           beer_id,
           brewery_id
   ) AS t1
   ANY LEFT JOIN
   (
       SELECT
           brewery_id,
           count(rating_score) AS count_for_that_brewery
       FROM beer_reviews
       WHERE created_at >= today()-{n_days}
       GROUP BY brewery_id
   ) AS t2 ON t1.brewery_id = t2.brewery_id
   ANY LEFT JOIN
   (
       SELECT
           brewery_id,
           stats_age_on_service
       FROM brewery_info
   ) AS t3 ON t1.brewery_id = t3.brewery_id
   GROUP BY
       t1.brewery_id,
       t2.count_for_that_brewery,
       t3.stats_age_on_service
   HAVING t2.count_for_that_brewery >= 150
   ORDER BY brewery_pure_average
   LIMIT {top_n}
    """)

scatter_plot_df_with_age = pd.DataFrame(brewery_pure_average, columns=['brewery_id', 'brewery_pure_average', 'rating_count', 'brewery_name', 'beer_count'])

Working with a DataFrame

Add two dotted lines that will pass through the median values of each axis. That way we can find out which breweries are above average, the best ones will be in the upper right area.

dict_list = []
dict_list.append(dict(type="line",
                     line=dict(
                         color="#666666",
                         dash="dot"),
                     x0=0,
                     y0=np.median(scatter_plot_df_with_age.brewery_pure_average),
                     x1=7000,
                     y1=np.median(scatter_plot_df_with_age.brewery_pure_average),
                     line_width=1,
                     layer="below"))
dict_list.append(dict(type="line",
                     line=dict(
                         color="#666666",
                         dash="dot"),
                     x0=np.median(scatter_plot_df_with_age.rating_count),
                     y0=0,
                     x1=np.median(scatter_plot_df_with_age.rating_count),
                     y1=5,
                     line_width=1,
                     layer="below"))

Add annotations to display median values by hovering:

annotations_list = []
annotations_list.append(
    dict(
        x=8000,
        y=np.median(scatter_plot_df_with_age.brewery_pure_average) - 0.1,
        xref="x",
        yref="y",
        text=f"Median value: {round(np.median(scatter_plot_df_with_age.brewery_pure_average), 2)}",
        showarrow=False,
        font={
            'family':'Roboto, light',
            'color':'#666666',
            'size':12
        }
    )
)
annotations_list.append(
    dict(
        x=np.median(scatter_plot_df_with_age.rating_count) + 180,
        y=0.8,
        xref="x",
        yref="y",
        text=f"Median value: {round(np.median(scatter_plot_df_with_age.rating_count), 2)}",
        showarrow=False,
        font={
            'family':'Roboto, light',
            'color':'#666666',
            'size':12
        },
        textangle=-90
    )
)

Let’s make our plot more informative by splitting breweries into 4 groups according to the beer range. The first group will include breweries with less than 10 brands, the second group for those holding 10-30 brands, the third one for 30-50 brands, and the last one for large breweries with >50 brands. We stored marker sizes in the bucket_beer_count list.

bucket_beer_count = []
for beer_count in scatter_plot_df_with_age.beer_count:
   if beer_count < 10:
       bucket_beer_count.append(7)
   elif 10 <= beer_count <= 30:
       bucket_beer_count.append(9)
   elif 31 <= beer_count <= 50:
       bucket_beer_count.append(11)
   else:
       bucket_beer_count.append(13)
scatter_plot_df_with_age['bucket_beer_count'] = bucket_beer_count

Next step is to perform age-based splitting

bucket_age = []
for age in scatter_plot_df_with_age.age_on_service:
   if age < 4:
       bucket_age.append(0)
   elif 4 <= age <= 6:
       bucket_age.append(1)
   elif 6 < age < 8:
       bucket_age.append(2)
   else:
       bucket_age.append(3)
scatter_plot_df_with_age['bucket_age'] = bucket_age

Let’s divide our DataFrame into 4 parts to build separate scatter plots with its own color and size.

scatter_plot_df_0 = scatter_plot_df[scatter_plot_df.bucket == 0]
scatter_plot_df_1 = scatter_plot_df[scatter_plot_df.bucket == 1]
scatter_plot_df_2 = scatter_plot_df[scatter_plot_df.bucket == 2]
scatter_plot_df_3 = scatter_plot_df[scatter_plot_df.bucket == 3]

Plotting

Now we are ready to build the plot, add our 4 brewery groups one by one, setting its key parameters: name, marker color, annotation transparency and text.

fig = go.Figure()
fig.add_trace(go.Scatter(
    x=scatter_plot_df_0.rating_count,
    y=scatter_plot_df_0.brewery_pure_average,
    name='< 4',
    mode='markers',
    opacity=0.85,
    text=scatter_plot_df_0.name_count,
    marker_color='rgb(114, 183, 178)',
    marker_size=scatter_plot_df_0.bucket_beer_count,
    textfont={"family":"Roboto, light",
              "color":"black"
             }
))

fig.add_trace(go.Scatter(
    x=scatter_plot_df_1.rating_count,
    y=scatter_plot_df_1.brewery_pure_average,
    name='4 – 6',
    mode='markers',
    opacity=0.85,
    marker_color='rgb(76, 120, 168)',
    text=scatter_plot_df_1.name_count,
    marker_size=scatter_plot_df_1.bucket_beer_count,
    textfont={"family":"Roboto, light",
              "color":"black"
             }
))

fig.add_trace(go.Scatter(
    x=scatter_plot_df_2.rating_count,
    y=scatter_plot_df_2.brewery_pure_average,
    name='6 – 8',
    mode='markers',
    opacity=0.85,
    marker_color='rgb(245, 133, 23)',
    text=scatter_plot_df_2.name_count,
    marker_size=scatter_plot_df_2.bucket_beer_count,
    textfont={"family":"Roboto, light",
              "color":"black"
             }
))

fig.add_trace(go.Scatter(
    x=scatter_plot_df_3.rating_count,
    y=scatter_plot_df_3.brewery_pure_average,
    name='8+',
    mode='markers',
    opacity=0.85,
    marker_color='rgb(228, 87, 86)',
    text=scatter_plot_df_3.name_count,
    marker_size=scatter_plot_df_3.bucket_beer_count,
    textfont={"family":"Roboto, light",
              "color":"black"
             }
))

fig.update_layout(
    title=f"The ratio between the number of reviews and the average brewery rating for the past <br> {n_days} days, top {top_n} breweries",
    font={
            'family':'Roboto, light',
            'color':'black',
            'size':14
        },
    plot_bgcolor='rgba(0,0,0,0)',
    yaxis_title="Average rating",
    xaxis_title="Number of reviews",
    legend_title_text='Registration period<br> on Untappd in years:',
    height=750,
    shapes=dict_list,
    annotations=annotations_list
)

Voila, the scatter plot is done! Each point is a separate brewery. The color shows the brewery beer range and when hovering we will see a summary including the average rating for the past 30 days, number of reviews, brewery name, and beer range. The dotted lines are passing through the median values we calculated with NumPy, they’re showing us the best breweries in the upper right. In our next article, we are going to create a breweries dashboard with dynamic parameters.

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