The United State federal budget is a complicated entity.
By many measures this public institution is the largest and most important in the world, but analyzing exactly how the money is dispersed can be difficult.
Weighing the Eagle
This difficulty is understandable: massive, diverse parts defy simply quantification, much less when they undergo annual changes. At least four entities inside the federal government itself are concerned with budget analysis.
Spending is broken down by agency, mandatory or discretionary sources, or overall function. Agencies are commonly known (EPA, NASA, NSF) and counting spending on programs you like/dislike is easy. But this picture is incomplete, since the entire budget is not cleanly divided among agencies. Mandatory and discretionary spending blur the lines further, since funding for some programs will pull from both sides, but not equally.
Spending by function shows how the entire pie is distributed. Agencies may draw funding from more than one function, but the board categories simplify digesting the priorities. The graph made by codex10 makes use of these functions.
The government organizes the function data with superfunctions, which contain functions, which contain subfunctions. All of the functions (and therefore dollars) are represented in the graph. Any entities that failed to reach at least 0.04% of GDP in any year are wrapped up into parent 'Other' bubbles to make the view manageable.
A few larger bubbles consist of many smaller functions, notably the 'Physical Resources'. This includes Transportation, Disaster Relief, Energy, Pollution Control, and more (see the referenced data for specifics). In 2013 this group accounted for more than $170 billion - a reasonable chunk compared to other spending, but only when lumped all together with their superfunction. This happens a few times in the data across the years.
Feel free to explore the chart and see how the federal government has spent money across the decades.
If you would like to comment or found a mistake, please email me.