ok so i’m trying to understand the structure of the whole OSM project. i generally like it but it’s confusing and i’m confused.

i’m specifically looking for satellite image data (landscape as seen from above, no infrastructure data, just real photography). i like satellite images a lot because it provides a much better feel for the landscape than infrastructure data alone. such as: how many trees are there, how much nature is there around, …

does OSM itself do this? (ideally without having to be logged in)

i found OpenMapTiles which seems to also provide satellite data; but i’m not sure what their relation to OSM is. are they a separate project?

  • Aniki@feddit.orgOPEnglish
    1·
    2 days ago

    OpenStreetMap under the hood is simply a database of key–value pairs assigned to nodes, lines, polygons, and “relations” between those three.

    yeah i suspected as much

    so this might sound wild at first but i think it makes sense to compare the data structures of a project like OSM to a computer game like minecraft. basically, in the minecraft world, there’s 3 separate types of data storage:

    • chunk storage is a 3-dimensional array that just stores the type of block found at each x,y,z-location. as such, reading the array (and taking the block with the highest z-value that is not air) gives you an aerial view. this is comparable to a photograph (aerial view).
    • structure storage. this tells you, for example, if you have a chest, what is inside it. this assignes function to physical space, similar to how OSM assignes meaning (house, street) to a chunk of physical space. This is where the “relations” between x,y,z-nodes and polygons comes in.
    • the third type is storage for movable objects, such as players moving around in the world; since they are not fixed objects, they cannot be assigned simple static x,y,z-coordinates so easily. but i think for OSM there’s no good analogy.

    Edit: And yes, OpenMapTiles is a separate thing, and any of its aerial imagery would also not be its own. It’s prohibitively difficult for but a few select organizations to maintain aerial imagery like that. You can read more here.

    I’ll read the link later, thank you.!