# Ground Zero Water And Shoreline Pass

This pass determines whether the current 1 km Ground Zero MVP tile needs ocean,
bathymetry, or shoreline handling inside the playable demo map.

## Result

The current Ground Zero tile does not contain ocean water or a shoreline inside
its 1 km bounds. First-pass ocean depth and shoreline mesh work is therefore not
required for this tile.

The analysis found no sea-level or near-sea-level samples:

- Minimum DEM elevation: approximately `3.16 m`
- Sea-level or below samples: `0`
- Near-sea-level samples at `<= 2.0 m`: `0`
- Low coastal samples at `<= 5.0 m`: `57,812` out of `1,000,000`

The tile is still coastal-influenced, and water remains important for gameplay.
For the MVP map, add a small freshwater source separately from ocean handling.
Ocean, bathymetry, coastline, and surf/shoreline systems should be handled when
the west and southwest neighboring coastal tiles are brought into scope.

## Source

- Tile: `gz_us_ca_pacifica_utm10n_e544_n4160`
- DEM:
  `Data/Terrain/Extracted/gz_us_ca_pacifica_utm10n_e544_n4160/gz_us_ca_pacifica_utm10n_e544_n4160_1m_dem_subset.tif`
- Analysis output:
  `Data/Terrain/Analysis/gz_us_ca_pacifica_utm10n_e544_n4160/gz_us_ca_pacifica_utm10n_e544_n4160_water_shoreline_analysis.json`

## Thresholds

- Sea level: `0.0 m`
- Shoreline buffer: `<= 2.0 m`
- Low coastal buffer: `<= 5.0 m`

## Implementation Decision

- Do not place an ocean plane in the current Ground Zero tile.
- Do not fake bathymetry in the current tile.
- Keep NOAA/NCEI bathymetry in the source plan for coastal/ocean neighbor tiles.
- Add gameplay water as a freshwater source item or small placed water actor in
  a later MVP map pass.

## Follow-Up

The next terrain/map pass should classify hills, slopes, streams, coastline
absence, and other visible landform features from the DEM so resource placement,
movement modifiers, and future World Partition stitching can use the same data.
