MLB Field Analysis

A tool for comparing the outfields of Major League Baseball.

Why? After hearing my dad complain that "that wouldn't have been a home run in <stadium_name>" enough times, I went looking for some data to find out how often he was actually right. I also wanted to learn D3.

There is surprisingly little easily-available highly-detailed information on ballpark dimensions. I really liked this diagram of all ballpark dimensions (which is very similar to diagrams found in the Baseball Prospectus), and wanted to create an interactive version with open data.

Installation

1. Install parcel: npm install -g parcel-bundler
2. Install dependencies: npm i
3. Run parcel index.js
4. Visit localhost:1234

About

Sources

Where did this data come from?

• This incredible 2015 Fangraphs post by Andrew Fox, where he provides piecewise functions for polar coordinates (!!) for each ballpark. I have no idea how he did this so accurately.
• Wikipedia

Data Entry

Since the original LaTeX wasn't provided, I used OCRmyPDF on the images. Then, lots of copy-pasting.

There are likely errors introduced here due to OCR issues and/or human error.

Accuracy

Beside the aforementioned data-entry issues, these equations seem fairly accurate when spot-checked against official dimensions (most within about a foot).

Additionally, this data is from 2015, so some fields may be outdated. Need to fix some renamed stadiums too.

Future directions

I'd love to get playable foul territory, but that would be a massive job.

Wall-height data is also something I'd like to explore.

Some type of input allowing you to give launch angle/velocity and direction to determine which stadiums hits would be home runs in would be cool, too.

Also, some real UI...

Contributing

TKTK but could really use checks, and a way to figure out wall height and playable foul territory.

Code Style

I know, I'm using unicode theta, and I really shouldn't.