{
  "bbox": {
    "lat_min": -90,
    "lat_max": 90,
    "lon_min": -180,
    "lon_max": 180
  },
  "width": 2880,
  "height": 1440,
  "elev_min": -32000,
  "elev_max": 32000,
  "dtype": "int16",
  "byte_order": "little",
  "row_order": "north_to_south",
  "col_order": "west_to_east",
  "reference_radius_m": 696000000,
  "source": "NASA SDO/HMI synoptic magnetogram CR2300 via JSOC/Stanford",
  "carrington_rotation": 2300,
  "carrington_date_start": "2025-07-19",
  "carrington_date_end": "2025-08-15",
  "rotation_period_note": "Carrington sidereal rotation 25.38 days",
  "value_kind": "magnetic_field",
  "value_unit": "gauss",
  "value_mapping": "elev_int16 = round(sign(B) * sqrt(|B| / 1500.0) * 30000), clipped to +/-32000; inverse (valid below ceiling): B_gauss = sign(elev) * (elev / 30000)^2 * 1500; ceiling reached at |B| ~= 1638 G; NaN/nodata -> 0",
  "value_mapping_rationale": "Signed sqrt compression spreads quiet-sun |B|~5G into elev~+/-700 for visible texture while active-region |B|~1000G map to elev~+/-24500 and |B|~1638G reaches the +/-32000 int16-safe ceiling. Full gradation is preserved across 5-1638 G (no early plateau). Previous bake used +/-10000 cap which clipped everything above |B|~167G to the same height, making active regions render as a flat tabletop."
}