How the map, terrain and 3D model on this page load.
Maps
A map surface here is usually a stitched top-down image. Instead of loading one gigantic picture, it can be split into many small map tiles at several zoom levels.
That stack of tiles is called a tile pyramid: zoomed out uses a few low-detail tiles, zoomed in asks for the sharper pieces under your screen. It is how the page can zoom into big stitched images without making every visitor download the whole thing up front.
Tiled web maps · Tile Map Service
Terrain
Terrain views care about height, not just colour. A 2.5D view uses that height information to give a flat map some shape, so slopes, bumps, and reconstruction errors are easier to read.
Some terrain can also be packaged as quantized mesh, a compact web terrain format that streams ground as small 3D tiles. It is useful for inspection, but it is still a viewer path, not a promise that every scan is survey-grade.
2.5D · Quantized mesh terrain · 3D Tiles
3D models
Most models here come from photogrammetry: overlapping photos solved into a textured mesh. The browser gets GLB files, rendered posters, lighter and fuller model choices, saved camera framing, and source-format notes where they matter.
Texture compression is treated as real delivery proof, not a label. If a model has ordinary WebP textures, it is described that way until an actual KTX2/BasisU asset exists and is served correctly.
glTF and GLB · KTX2 textures
Why the variants exist
Browsers, screens, networks, and media types do not agree on one perfect file. The page stays simple, while the saved asset details keep source kind, quality level, preview confidence, dimensions, format, and fallback intent.
Each asset gets the special handling it needs. The goal is not to show off file formats; it is to make the page choose the right thing quietly, then explain the machinery only when you ask.
