# Questions tagged [dbscan]

DBSCAN means density-based spatial clustering of applications with noise and is a popular density-based cluster analysis algorithm.

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### Is there a way to automatically split large clusters that are greater than some maximum number of points?

I ran HDBSCAN on these coordinates and got some clusters but some are too large. HDBSCAN has a minimum cluster size parameter, but no maximum size. All I want is to intuitively divide larger clusters ...
1 vote
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### How to do search/cluster over a million points?

I've a practical question in the areas of clustering/semantic search and would like to get some thoughts. Refer the figure for more details on this hypothetical situation. Imagine I've 2 query ...
1 vote
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### How does HDBSCAN generate cluster hierarchy?

HDBSCAN generates the minimum spanning tree where each vertex represents the data point whereas the edges represent the mutual reachability distance. But how does it generate the cluster hierarchy? I ...
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### Algortihm for clustering 2d grid-like scattered points

I struggle to find a way to cluster points scattered on a 2D map. The points are mostly following parallel lines (more or less curvy) and are crossed by other parallel lines in another direction. Here ...
809 views

### Why is UMAP used in combination with other Clustering Algorithm?

I've noticed that UMAP is often used in combination with other clustering algorithms, such as K-means, DBSCAN, HDBSCAN. However, from what I've understood, UMAP can be used for clustering tasks. So ...
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### Can we set a maximum distance between pairs in a cluster with DBSCAN?

I'm trying to cluster embedded words (embedded using FastText) into words that are very similar e.g helloworld, heloworl and <...
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### In DBSCAN, can the distance between a Noise Point and Border Point be less than Epsilon?

In DBSCAN: A core point is a point which has at least "MinPts" points inside its Epsilon radius. A border point is a point inside the Epsilon radius of a core point, but it has a number of ...
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### How to perform feature selection technique using DBSCAN?

I have a small doubt regarding the feature selection using DBSCAN as I am new to this algorithm; I was performing DBSCAN using the scikit-learn package, and I could not understand what this algorithm ...
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### How to do DBSCAN clustering with mixed variables (numerical features and binary/ordinal variables)?

I have a question written at the end of the post which refers to the "Distances" paragraph. The other first two paragraphs give additional info. Context I'm working on a project where I have ...
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### How to perform some calculations after dbscan clustering

I have performed a clustering with geospatial data with the dbscan algorithm. You can see the project and the code in more detail here: https://notebook.community/gboeing/urban-data-science/15-Spatial-...
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### DBSCAN clustering using classification algo within each clusters formed

I am using DBSCAN algo. on "pima indian diabetes" but not able to properly cluster the data. Also I want to use classification algo within each cluster and compare the accuracy of each ...
1 vote
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### Incorporating error values (uncertainties) into DBSCAN

Suppose I have a set of coordinates (x,y,z), corresponding to ~800 points. I am currently using DBSCAN with a custom metric function (taking angles as an input, ...
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### I need help with which features to use for clustering

I am using this dataset: https://www.kaggle.com/datasets/sobhanmoosavi/us-accidents and so far I have successfully cleaned the dataset as well as reduced the size of the features and records. I have ...
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### DB-Scan with ring like data

I've been using the DBScan implementation of python from sklearn.cluster. The problem is, that I'm working with 360° lidar data which means, that my data is a ring ...
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### Is HDBSCAN a agglomerative hierarchical clustering?

I am looking at HDBSCAN and wondering whether it is Divisive or Agglomerative? I understand the two approaches, but I cannot seem to grasp which HDBSCAN utilises. Looking for some elaboration. https://...
1 vote
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### When use standardization, normalization or both?

I have a dataset with variables with different scales as shown in the figure below. I need to group individuals together and I'm testing algorithms like Kmeans and DBScan. In all tests I'm extracting ...
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### need an explanation of the For Loop in the DBSCAN algorithm Demo

In the following code of the DBSCAN algorithm, as a beginner I need an explanation for what happens to the data in the bottom for loop and why ? Generate sample data ...
112 views

### Distance between any two points after DBSCAN

DBSCAN is a clustering model which is robust to detect the outliers also. A parameter $\epsilon$ i.e. radius is an input of the algorithm, a point is said to be outlier if it's circle with radius \$\...
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### How to add 'other' as one group to clustering algorithm inference pipeline

I have few clustering algorithms tuned having 5 cluster. I want 6th cluster if new data does not belong initial 5 cluster fall in 6th cluster. 6th cluster [ say other category] consist of all data ...
495 views

### How to group every data point with HDBSCAN to some group to have no noise?

TASK I am clustering products with about 70 dimensions ex.: price, rating 5/5, product tag(cleaning, toy, food, fruits) I use HDBSCAN to do it GOAL The goal is when users come on our site and I can ...
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### Comparison between DBSCAN and single linkage hierarchical clustering

I am studying clustering algorithms and I want to find a good example where single link hierarchical clustering algorithm returns better cluster results than DBSCAN (having provided valid parameters). ...
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### Estimate eps value in DBSCAN using KNN algorithm

I would like to estimate the best eps value for the DBSCAN algorithm on this dataset by following this set of rules: Set a minPts: 10 Compute the reachability distance of the 10-th nearest neighbour ...
817 views

### Understanding and find the best eps value for DBSCAN

I'm trying to run the DBSCAN algorithm on this .csv. In the first part of my program I load it and plot the data inside it to check its distribution. This is the first part of the code: ...
1 vote
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### Clustering Tweet Data using DBSCAN Algorithm

I am doing a tweet clustering using DBSCAN algorithm. I use all the preprocessing steps and convert sentences to vector format before applying the algorithm. ...
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### DBSCAN on textual and numerical columns

I have a dataset which has two columns: title price sentence1 12 sentence2 13 I have used doc2vec to convert the ...
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### Building an unsupervised learning model to detect suspicious transactions using DBSCAN [closed]

I am working on building a unsupervised learning model to detect suspicious transactions using DBSCAN. Do I train the model on all data columns (columns like account number, transaction date, ...
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### How to study the effect of eps in sklearn.cluster.DBSCAN?

I posted this question on stackoverflow.com and have not received any answer. In case I get an answer from one of them, I will inform on the other. I have a dataset and is requested by my professor ...
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### Looking for spatial clusters and anomalies. Is DBSCAN the right tool?

I have a regular 2D grid of data points (X, Y) with each point having a value. I'd like to identify clusters and then anomalies that don't belong to those clusters. I'm trying to understand the best ...
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### Shall I use ordinal encoding or One-Hot-Encoding when using DBSCAN for content clustering on websites?

I want to cluster the preparation steps on cooking recipes websites in one cluster so I can distinguish them from the rest of the website. To achieve this I extracted for each text node of the website ...
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### DBSCAN Clustering

I used K-means to get the number of clusters for my data(Elbow Method). Then I was trying to see if for some specific hyperparameters can we get the same number of clusters for DBSCAN. I tried Brute-...
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### How may I may fit the cluster number while it is going to the outside of the X-axis and when visualizing clusters in two dimensions?

I am writing code for DBSCAN clustering. I find the eps value which is 0.12 with the help of ...
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### Nice real data sets for testing DBSCAN?

I'm looking for real datasets on which I could test my DBSCAN algorithm implementation, that is, a dataset of points in (ideally 2 dimmensional) space, or a set of nodes and info about the distances ...
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### Types of artificial anomalies

I am working on some algorithms for anomaly detection The dataset is clean our anomalies so I want to add some artificial anomalies. I have added some anomalies. I get the maximum value of the ...
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### Classifier for DBSCAN [closed]

I have written a code that uses DBSCAN and tries to find the most appropriate eps for my dataset, trying to include most of the data inside a cluster. The problem is that DBSCAN is not a classifier ...
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### How to use Cosine Distance matrix for Clustering algorithms like mean-shift, DBSCAN, and optics?

I am trying to compare different clustering algorithms for my text data. I first calculated the tf-idf matrix and used it for the cosine distance matrix (cosine similarity). Then I used this distance ...
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### Estimating minPts in DBSCAN for document layout clustering

I am trying to choose parameters for DBSCAN clustering algorithm, in particular minPts. The Wikipedia article suggests a rule of thumb to derive minPts from the number of dimensions D in the data set....
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### Plots of data using DBSCAN algorithm not making sense

I am using clustering for my data. Since the DBSCAN algorithm will also tell me an estimate of clusters that I can use, I have used DBSCAN. I have tried for the ...
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### Clustering Small Text Descriptions

Im presented with a unique text classification problem. Im given a list of descriptions each containing 3-8 words. I know that there are some descriptions that are nearly the same, but the majority ...
1 vote
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### what arguments should I pass to dbscan or optic in order to divide the data in a specific way

I have thousands of very similar datasets that needs to be divided in diagonal way to two groups. for example: and I tried to play with the argument of dbscan and optic as epsilon and minPoints and ...
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### Is it safe to use labels created from unsupervised model to train a supervised model using the same data?

I have a dataset where I have to detect anomalies. Now, I use a subset of the data(let's call that subset A) and apply the DBSCAN algorithm to detect anomalies on set A.Once the anomalies are detected,...
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### The actual results and results from pickle files are not matching in pandas for DBSCAN clustering

I've built a DBSCAN clustering model. The output result and the result after using the pickle files are not matching. Based on HD and MC column, I am clustering WT column. ...
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1 vote
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### T-DBSCAN - Implementing STOP logic

I am attempting to implement the T-DBSCAN algorithm described in T-DBSCAN: A Spatiotemporal Density Clustering for GPS Trajectory Segmentation. I have been able to implement most of the logic between ...
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### Are DBSCAN and dbscan from the sklearn.cluster package different?

I'm new to DBSCAN. I was looking at a few examples online and came across a few instances where the following lines were used while importing the dbscan module: <...
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### How to properly use approximate_predict() with HDBSCAN clusterer for text clustering (NLP)?

I have approached text clustering using HDBSCAN based on this article which describes how to do this in R. I've re-written this in Python using this library. The approach is to first calculate TF-IDF ...
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### DBSCAN: How does a quantile of kNN relate to the share core points?

I read this answer by Anony-Mousse to an other question related to density based clustering and how to potentially come up with an eps. It states, that if you want 90% of you points to be core points, ...
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### DBSCAN clustering on document [updated]?

I am new in topic modeling and text clustering domain and I am trying to learn more. I would like to use the DBSCAN to cluster the text data. There are many posts and sources on how to implement the ...
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### Clustering based on geolocation pair

I am trying to process a large set of location data where a list of start and end coordinate is given. For example, ...
1 vote
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### How to find anomalies/outliers in Panel Data?

I have panel data based on 900000 different entities with 384 time steps and the data is not normally distributed. I am looking for outliers/anomalies, this is unsupervised as I have no examples of ...