Until now, we had several inconsistencies in how we displayed boundaries across zoom levels. Take, for instance, the border between North Korea and South Korea. At mid-zoom levels, we drew three separate lines for the demilitarized zone. Zoom in, and it disappeared. Zoom out, and it disappeared again.
That happened because we used a mixture of datasets, which made it difficult to deliver a consistent product across zoom levels. A boundary that existed in the source data at zoom 8 didn't necessarily exist at zoom 4, or may have even been in a slightly different place. This also led to some boundaries being marked as disputed at some zoom levels but not others.
What We Changed
We overhauled our boundary processing pipeline to remove these inconsistencies and streamlined how we serve them. Now, every boundary is consistently marked as disputed or non-disputed at every zoom level, and we've cleaned up inconsistencies, like the Korean border mentioned in the intro.
We've also normalized the claimed_by property that describes which country or entity claims a border. The values are now ordered consistently across the dataset. This makes it easier to apply styling and enables us to deliver more efficient tiles.
An Example of Efficiency
We applied the same boundary optimization we used for water features in our June 2026 update. Each logical boundary is now a single line, and we merge connected features that share the same attributes. For the technical details on how this works, read How We Fixed Water Feature Rendering Across All Zoom Levels.
The visual output stays the same (or even improves in a few cases!) while the tiles are typically smaller. Smaller tiles matter for apps that render millions of boundaries or run on slow connections.
What's Coming Next
We're exploring ways to better communicate who claims, recognizes, and disputes contested areas. We're still working out the best way to do this, but the end goal is to surface more nuance so you can construct the view your users expect.
If you're styling boundaries today and need a particular treatment for disputed areas, tell us what you need at support@stadiamaps.com. It feeds directly into what we build next.