Before building dashboards or creating visualizations in Tableau—or even preparing data for use in ArcGIS Pro—the data itself needs to be structured, clean, and ready for analysis. While some data preparation can be done directly in Tableau or ArcGIS Pro, Tableau Prep provides a dedicated environment for cleaning, combining, and shaping data before analysis begins.

Within the broader Tableau workflow, Tableau Prep serves as the data preparation layer. Data is first connected and transformed in Tableau Prep, then exported as a clean dataset that can be used in Tableau Desktop to build visualizations, dashboards, and reports. Separating preparation from visualization helps create a more organized and scalable analytics process.

Instead of relying on manual spreadsheet edits or complex scripts, Tableau Prep offers an interactive workflow where users can explore their data, identify issues, and apply transformations step by step—all while leaving the original source data unchanged.

Extracting tables from PDF files

Data doesn’t always come in neat spreadsheets. Sometimes it’s locked inside PDF reports, which makes it harder to use directly for analysis. Tableau Prep helps solve this by allowing you to import PDF files and automatically detect tables within them. Once the tables are extracted, you can review the results, clean up any formatting issues, and structure the data so it’s ready to use.

This makes it much easier to turn static reports into datasets you can actually analyze—without manually copying and pasting information into a spreadsheet. In the video below, you’ll see how to bring a PDF into Tableau Prep and extract the tables so they’re ready for the next step in your workflow.

In the video below, I show how to use Tableau Prep to extract tables from a PDF file and prepare the data for analysis.

How to clean and prepare Excel data

Tableau Prep allows you to extract and prepare data from an Excel file that may contain one or multiple worksheets, while keeping the original file intact. By creating clean steps and queries, you can generate multiple outputs and build a flexible workflow that can easily be revisited and modified. Below, you can see how it is done.

Combining multiple Excel files with weather data using a Union

In some cases, data may be stored across multiple tables even though the structure of the tables is identical. For example, temperature and precipitation data might be recorded separately for different weather stations. While each table contains the same fields and the same number of variables, the records correspond to different stations.

Using a union in Tableau Prep, these tables can be combined into a single dataset. This allows you to merge all records into one table while preserving the common structure of the data. In this case, the goal is to create one consolidated file containing the complete list of weather stations in Arizona, along with their corresponding temperature and precipitation records. By unioning the tables, you can simplify the dataset and make it easier to analyze, visualize, or map the information within Tableau. See below how to do it!