Comment by shadowgovt
Comment by shadowgovt 2 days ago
Replicated at different resolutions depending on your zoom level.
One patch at low resolution is backed by four higher-resolution images, each of which is backed by four higher-resolution images, and so on... All on top of an index to fetch the right images for your zoom level and camera position.
Except in the case of a format like JPEG, there is no duplication - higher layers are used to "fill in the gaps" in the data from lower layers.