I can help you to..

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• Harvest data from different sources like APIs, SQL databases or messy Excel spreadsheets.
• Reformat and reshape data to make further analyses easier.
• Clean datasets removing outliers and abberant data.
• Create reproducible data preparation workflows
• Automatize the creation of data related reports

Example:

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• I collected tweets containing the #surf for 9 months to study how surfers use social media. I used the twitter API and made the data collection automatic thanks to a personnal webserver and a custom R script.
• I created a dashboard for a company called Terres Inovia. It is directly plugged on their SQL database and allows to access its information in real time.

Contact me

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Tell me more about your project at yan.holtz.data@gmail.com to see if we can work together.

I can help you for

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• Exploratory analysis of a dataset.
• Creation of clean and reproducible reports using R Markdown.
• Application of statistical methods on your dataset.
• Creation of custom scripts for analysing your data automatically

Example:

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• I'm the author of several scientific publications where I was in charge to explore and understand complex dataset in order to answer scientific questions.
• I recovered information about crypto currency prices on different exchanges and explored the data looking for arbitrage opportunities.

Contact me

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Tell me more about your project at yan.holtz.data@gmail.com to see if we can work together.

I can help you with:

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• Creation and review of graphs for scientific publication.
• Development of data application using R and Shiny.
• Creation of custom data visualization for the web using d3.js.
• Dashboard creation for real time data analysis.
• Visualization of geospatial data.

Example:

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• A website describing research results on mental disorders comorbidity.
• Data to viz: a decision tree leading to the most appropriate chart type for your data.
• See many more examples in the portfolio section of this website.

Contact me

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Tell me more about your project at yan.holtz.data@gmail.com to see if we can work together.

Description

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A group of researcher from the Institute of Molecular Bioscience investigated the geographic clustering of genetic variants that influence complex traits and disease risk in a sample of ~450,000 individuals from Great Britain.

I built a web application that goes in support of the paper intitled Genetic Consequences of Social Stratification in Great Britain.

The shiny application allows to visualize the geographic distribution of any trait. It allows to custom color scales, region shape and to apply a cartogram algorithm to the map. Moreover, the tool allows one to upload its own data to benefit this dataviz tool.

Read more

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The web application is available online. You can read the scientific paper on BioArXiv. The source code of the project are of course on Github.

Description

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Using Python and the open-source library Panel, we were able to create an interactive app that displays visualizations of carbon emissions data for different countries. Panel makes it easy to create custom interactive web apps and dashboards by connecting user-defined widgets to plots, images, tables, or text.

With the help of HVPlot, I was able to create beautiful and informative charts and graphs that show how emissions have changed over time. This project was not only a great way to practice my coding skills, but it also helped me gain a better understanding of how carbon emissions are affecting our planet. I hope this dashboard can serve as a useful resource for others who are interested in learning more about climate change and its impact on the world.

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Description

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Comorbidity is defined as the presence of 1 or more disorders in relation to an index disorder. I've been involved in a project with the Queensland Brain Institute (Australia) and the University of Aarhus (Denmark) to build an interactive website allowing to explore the discovered patterns of comorbidity between mental disorders.

The online tool goes with the publication in Jama Psychiatry. Several interactive graphs are available with export options and more. The tool was created using R and Shiny, plus several Html widgets for interactivity.

Read more

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The web application is available online. You can read the scientific paper on Bioinformatics. The source code of the project are on Github.

Description

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Terres Inovia is a French company carrying out applied research on oilseed plants and protein crop. It phenotypes the main varieties of 20 crop species in many locations for several traits every year. This information is stored in a massive SQL database.

I created a dashboard allowing to explore these data. It allows to quickly understand what variety performs well in what kind of environmental condition. It thus has a direct impact on advices provided to farmer in France.

The dashboard was created using R and Shiny. It requires several HTML widgets to create interactive graphs, and specific packages to interact with the database. Here is a screenshot of the welcome page of the application:

Read more

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I can't provide more information on this project for privacy reasons.

Description

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I have used this project to provide introduction to data analysis using SQL language, which should be a must tool for every data scientist - both for getting access to data, but more interesting, as a simple tool for advance data analysis. The logic behind SQL is very similar to any other tool or language that used for data analysis (excel, Pandas), and for those that used to work with data, should be very intuitive.

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The project involves data analysis using SQL on a European soccer database. The project involved creating a connection to the database and identifying the available tables, including lists of countries, leagues and their countries, teams, and matches. Basic analytics were conducted using SQL queries, including the use of subqueries and functions to extract insights from the data. Overall, the project required a solid understanding of SQL syntax and the ability to manipulate and analyze complex data sets.

Description

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Stroke is a serious medical condition that affects millions of people worldwide. It occurs when there is a disruption in blood supply to the brain, leading to cell death and permanent brain damage. Identifying and predicting the likelihood of stroke is crucial for preventing and treating the condition.

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a stroke prediction model. Using a dataset that includes factors such as gender, age, hypertension, and more, I conducted exploratory data analysis to gain insights into the relationships between these variables. From there, I utilized seven different machine learning models to predict the likelihood of stroke. After comparing the results, the LGBMClassifier model proved to be the most accurate. .

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The project showcases my proficiency in data analysis and machine learning techniques. I am confident that this stroke prediction model could have real-world applications in the medical field and could potentially aid in the prevention and treatment of stroke. .

Description

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UNICS is a web app that helps you computing the standard error of allele frequency estimations of future pool-sequencing experiments based on different parameters. You can use it trough the online version and read the related publication.

Application looks like this:

Read more

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See the associated github repository for more information and source code of the project.

Description

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I created an R script that recovers all tweets containing the hashtags #surf and run it on a webserver for about 9 months. I recovered more than 400k tweets. Some of them being geolocalized for both home and current location, it is possible to deduce where surfers travel.

Here is an overview of the result:

Read more

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See the dedicated page in data-to-viz.com that tells more about this project, with explanation on how to build a connection map.