Welcome to Yan Holtz's homepage.
I'm a data analysis and data visualisation freelancer available for hire.

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Hi, I'm Yan.

My job consists to help companies and researchers to analyse their datasets. I am skilled for most of the data-science steps: data pre-processing, application of statistical methods, data visualization and results communication.

After having worked for famous research institutes like the University of Queensland and private companies like Terres Inovia, I'm now a freelancer available for hire.

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2012 Master Degree 2015 Data Analyst at INRA 2017 Freelance - Data analysis Queensland Brain Institute

What can I do for you?

Let me help make better use of your data. My expertise can be used to clean, analyse, interpret and visualize your data.

Data Management

Data harvesting, cleaning and reshaping. Let's build an automated workflow.


Data Mining

Let me crunch the number for you and find the hidden insight in your data.



I can build stunning dataviz or dashboards to convey your results efficiently.


Teaching & Training

I love sharing my passion for analytics and dataviz. See what courses I have for your team.



A few stories about statistics, R, dataviz. More or less linked with our world, always related to data

From Data to Viz - A classification of graphics based on input data format

July 2018 - 6 minutes read

I’m delighted to announce a new dataviz project called Data to Viz. It is a classification of chart types based on input data format. It comes in the form of a decision tree leading to a set of potentially appropriate visualizations to represent the dataset. - Read more

Pimp my RMD - A collection of tips for R Markdown

July 2018 - 2 minutes read

R markdown creates interactive reports from R code. I’ve created a document that provides a few tips I use on a daily basis to improve the appearance of my html outputs (my memory aid). This document is built using R Markdown and hosted on Github. - Read more


I've developped several websites dedicated to data visualization. These resources are visited about 30.000 times a day.

from Data To Viz

A classification of charts based on their input format, and a lot of trick and tips


R Graph Gallery

Hundreds of R graphics, always with the reproducible code provided.


Python Gallery

A gallery of charts made with python, with a focus on Matplotlib and Seaborn.


D3 Graph Gallery

D3 is the ultimate tool for data visualization on the web. Tedious but limitless.



A glimpse of the projects I've been working on


Feel free to contact me for any question. For open source project, please open an issue or pull request on Github. If you want to follow my work, reach me on Twitter. Otherwise, send me an email at yan.holtz.data@gmail.com.

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