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A single tiled elevation coverage over a local directory of DTED tiles (.dt0/.dt1/.dt2), built by create: each 1° cell is served from the finest level present (dt2 > dt1 > dt0) — one pyramid, one cache, no duplicated data. Coarse cells upsample smoothly via bilinear windowed reads; zoomed-out grids sparse-sample a per-cell overview off the render thread (the ATAK NodeElevationData pattern).