Add TiledDiskArray

[felixcremer]

Add a TiledDiskArray type which handles a collection of tiles that lay in the same grid with a predictable pattern .

[rafaqz]

Could we use this to lazily wrap a tile server?

[felixcremer]

Main problem might be, that a Tile Server has color values and not actual array values. But this might work for wrapping a tile server and giving the RGB values from the pngs.

This would currently expect a function that would from a given tile position return a matrix of the data in this position. So we could have a function that reads the data from the tile server.

The interface we are aiming for currently is this:

using ArchGDAL

function geturl(east, north) 
    baseurl = "https://download.geoservice.dlr.de/FNF50/files"
    xsym, xval = if east < 180
        'W',180-east
    else
        'E', east-180
    end
    ysym, yval = if north < 90
        'S', 90-north
    else
        'N', north-90
    end
    xpadround = xsym * lpad(Int(round(xval, RoundDown, digits=-1)), 3, "0")
    ypadround = ysym * lpad(Int(round(yval, RoundDown, digits=-1)), 2, "0")
    xpad = xsym * lpad(xval, 3, "0")
    ypad = ysym * lpad(yval, 2,"0")
    tdm = "TDM_FNF_20_" * ypad * xpad
    join([baseurl, ypad, xpadround, tdm, tdm * "_cog.tif"], "/")
end

function gettile(east, north)
    response = HTTP.head(geturl(1,1), status_exception=false)
    if response.status == 200
        ArchGDAL.readraster("/vsicurl/"*geturl(east, north))[:,:]::Matrix{UInt8}
    else
        fill(UInt8(3), (2001,2001))
    end
end

A = DiskArrays.TiledDiskArray{UInt8,2}(gettile, (360,180), (2001,2001))

[meggart]

remove

[meggart]

remove

[meggart]

Can you use this definition instead:

struct TiledDiskArray{T,N,F} <: AbstractChunkTiledDiskArray{T,N}
    tilefunction::F
    tilenum::NTuple{N,Int}
    tilesizes::NTuple{N,Int}
end

[asinghvi17]

Might be worth having the tile definition be GridChunks instead - for example the Copernicus DEM has irregular sizes

[felixcremer]

Do you have a link to that?

[asinghvi17]

https://copernicus-dem-30m.s3.amazonaws.com/readme.html

[rafaqz]

Is tilesizes just tilesize? What does the pluralisation mean?

[meggart]

Superseded by #300 sorry @felixcremer, I could not push to your branch