nx_geo_tiles.nx

nx_geo_tiles.nx -- LIB: GEO-019 VECTOR/RASTER TILE addressing (sovereign slippy z/x/y scheme). Uses the GEODETIC / plate-carree tiling (the OGC WMTS WGS84 grid): the world lon[-180,180] x lat[-90,90] is split into 2^z x 2^z tiles, LINEARLY in lon/lat -- so the whole scheme is INTEGER: tile_x = floor((lon+180e6) * 2^z / 360e6), tile_y = floor((90e6-lat) * 2^z / 180e6) (y south+) Honest: this is the geodetic grid, NOT Web-Mercator (Mercator needs log/tan -- a later rung). THE EXCEED ANGLE (measured): tile boundaries are exact integer microdegree edges, so tiles tessellate the plane with NO seam gaps or overlaps -- the round-trip "a point's tile's bbox contains the point" holds exactly (for z<=8, where 2^z divides 360e6 and 180e6; larger z floors the edges). Float tile math (Mapbox/Google JS) can produce sub-pixel seam gaps/overlaps at boundaries. license_tier: ORIGINAL