It depends on the topic. When it comes to things like interstate commerce, you are correct -- the states don't each have treaties with each other.
But when it comes to other things, like education, that's very much a local function. The feds set minimum best practices (enforced by the threat of removing funding), but it's up to the tens of thousands of local school districts to decide what to teach their children.
Some of those local school districts are huge, on the order of 10's of thousands of students. Others can be as small as 15 or 20 students, or even one individual school.
When it comes to the topic at hand -- GIS information -- It is pretty much a county situation. There are numerous competing GIS standards and products, and each county or municipality chooses the software that works for its needs, and budget.
So, yes, there is creeping federalism in the United States. But claiming "it's not true and hasn't been for over a century" shows a lack of understanding of local civics.
I think the US shows itself to be pretty homogeneous, with some differences between the rural, suburban, and urban areas, but not much.
I can smoke weed legally for recreational purposes where I am here. Where I grew up I'd be thrown in jail.
Texas has no zoning laws of any kind. You can build any kind of building for any purpose anywhere (I'm sure there's still restrictions, but there's no zones per se.)
States have wildly different speed limits on highways. Different levels of allowed alcohol.
This is just off the top of my head without googling, I'm sure there's probably even bigger examples as well.
Federal databases of postal addresses don't really have any reason to maintain data on the structures.
Some fire fighting authorities have building layouts for recently built buildings. They may all have their own methods for storing the data, and the coverage is confusing enough that the bodies and budget authorities responsible for fighting any long lasting wild fire frequently change.
Properties lines are usually recorded and maintained at the county level, and enforced by a county court and sheriff at their direction, but this too is not the case everywhere.
It is not outlandish to think that there are multiple federal databases that include all of the data on buildings in the US, whether at the Department of Defense, or at multiple agencies within the Department of Homeland Security. However, it seems common that only data collected as a side effect of the regular course of doing government business are released to the public, but data sets created as part of some form of security-related goals are not released to the public.
[1] https://www.census.gov/construction/bps/how_the_data_are_col...
We just had a Supreme Court ruling affirming states’ anti-commandeering rights [1].
[1] http://www.scotusblog.com/2018/05/opinion-analysis-justices-...
There is probably a separate db (if its even a db) for each county. It is very much a data cleaning nightmare from my limited experience.