Lecture Note
University
University of California San DiegoCourse
DSC 207R | Python for Data SciencePages
3
Academic year
2023
anon
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7
Live Code, Clustering Creating a Clustering Model to Analyze Weather Data Using Python andScikit-Learn Do you need to study weather information at a finer level? Do you wish to learn about the patterns and trends in this data to aid in making decisions? If so, you've arrived to the correctplace. In this post, we'll look at how to use scikit-learn and Python to do clustering analysis tocreate a large-scale model of the weather at a nearby station. Let's import all the required libraries first. Although it's not technically necessary to import every library at the start of a notebook, doing so makes the code's dependencies clearer andeasier for end users to understand. The minute weather.csv data file, which containsreadings at the minute interval, will be imported using Pandas. Almost 1.5 million records in13 columns make up the data set. After importing the data, we should check our understanding of the data description by exploring with the data frame. Use the head function to get the first five rows of the data andexplore the data values and null values. This is a crucial step for any analysis. For analysis purposes, we can further sample the data by downsampling to every 10 minutes. This will reduce the data set size to one-tenth of the original data set, which will bemore manageable for clustering analysis. We'll assign the downsampled data to a new dataframe called "sampled_df." Let's describe this data set. We'll use the transpose operation to turn columns into rows and vice versa, which makes the data easier to read. After the describe operation completes,we'll check out the mean values of each measurement. The mean for air pressure is 916, airtemperature is 50.4, and so on. Now, let's perform clustering analysis on this data set. Our goal is to create 12 clusters, which will help us identify patterns and trends in the data. We'll use the KMeans algorithm,which is one of the most popular clustering algorithms in use today. To prepare the data for clustering analysis, we'll drop the row ID column, which is an identifier and not relevant for clustering analysis. Then, we'll scale the data usingStandardScaler to ensure all features are on the same scale. Scaling is important becauseclustering algorithms operate on the basis of distances between points. We'll create a KMeans object and fit it to our data. The fit method performs the clustering analysis on the data set, and the predict method assigns each point in the data set to itsnearest cluster. Finally, we'll add the cluster assignments to the sampled_df data frame, sowe can analyze and visualize the results.
Let's visualize the clusters using a scatter plot. We'll use Seaborn's lmplot function to create the scatter plot, which will show the relationship between air temperature and relativehumidity. The scatter plot will also color-code each point based on its cluster assignment. We can see that the clusters are clearly separated from one another after making the scatter plot. This illustrates how well the KMeans algorithm identified patterns and trends inthe data collection. Now that we have this knowledge, we may use it to guide ourdecision-making. As a result, clustering analysis is an effective method for spotting patterns and trends in huge data sets. In this article, we looked at how to use Python and Scikit-Learn to doclustering analysis on weather data. We were able to find 12 unique clusters bydownsampling, scaling, and applying the KMeans method. We then used a scatter plot toshow these clusters. We sincerely hope that this paper has been useful in demonstratingclustering analysis's use with meteorological data. Scaling and Clustering with Python: A Comprehensive Guide When it comes to data analysis, scaling and clustering are two essential techniques for making sense of large datasets. In this guide, we will explore how to scale and cluster datausing Python, step-by-step. Scaling data involves transforming numerical data into a standard scale, to ensure that values from different columns are comparable. Clustering, on the other hand, involvesgrouping similar observations together into clusters based on their features. To get started, let’s assume that we have a dataset that we want to cluster into 12 groups based on certain features. We will use Python’s scikit-learn library to perform scaling andclustering operations. Preparing the Data First, we need to prepare the data by selecting the features we want to use for clustering and scaling the data. We can do this using a sample data frame that contains a tenth of ourdata. We then reduce the number of columns in the data to the six features that we want touse for clustering. We call this new data frame select_df. The data in select df are then scaled using a conventional scaler using the fit transform() function. Prior to applying the transformation to the data frame, this function determines howmuch the dataset needs to be scaled. This function's result is attributed to X, which willsubsequently serve as the input for our k-Means modeling. from sklearn.preprocessing import StandardScalerscaler = StandardScaler()X = scaler.fit_transform(select_df)
After scaling, we can display the values in X to ensure that they have been scaled properly. These scaled values will be between a minimum and maximum number and can becompared to the original values in select_df. K-Means Clustering Then, we are ready to perform k-Means clustering on our data. We will use the KMeans() function from scikit-learn to create a k-Means object called kmeans, with 12 clusters. We willthen fit this object to our scaled data, X. from sklearn.cluster import KMeanskmeans = KMeans(n_clusters=12)model = kmeans.fit(X) After fitting the model, we can extract the cluster centers using the cluster_centers_ attribute of the model, and assign it to a variable called centers. centers = model.cluster_centers_ centers will be an array containing the cluster centers for each of the 12 clusters, with eachcluster center represented by seven floating-point numbers, denoting where the clustercenter stands in the seven dimensions of our feature space. Visualizing the Clusters Now that we have our cluster centers, it would be useful to visualize them to better understand how our data is clustered. We can do this using a scatter plot, where each pointrepresents a cluster center and its position in the plot is determined by its coordinates in thefeature space. import matplotlib.pyplot as pltplt.scatter(centers[:, 0], centers[:, 1])plt.show() This code creates a scatter plot of the first two dimensions of our feature space. We can change the dimensions plotted by changing the indices in the centers array. Using Python's scikit-learn module, scaling and clustering are two crucial data analysis approaches. We may use k-Means clustering to put related observations together intoclusters by choosing the features we wish to utilize for clustering and scaling the data usinga common scaler. The cluster centers can then be extracted and shown to help uscomprehend how our data is clustered.
Live Code Clustering Analysis with Python
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