Coordinate Systems¶
Output Coordinate System¶
All data is distributed in WGS84 (EPSG:4326) geographic coordinates (latitude, longitude).
Original Coordinate Systems¶
Some FVCOM model domains were originally configured in projected coordinate systems and were transformed during standardization:
| Location | Original System | Transformation |
|---|---|---|
| Aleutian Islands | Geographic (lat/lon) | None |
| Cook Inlet | Geographic (lat/lon) | None |
| Western Passage | UTM Zone 19 (NAD83) | to WGS84 |
| Piscataqua River | UTM Zone 19 (NAD83) | to WGS84 |
| Salish Sea | UTM Zone 10 (NAD83) | to WGS84 |
Transformation Details¶
UTM-to-WGS84 transformations were performed using pyproj with the following parameters:
- Source CRS: NAD83 UTM (Zone 10 or 19 depending on location)
- Target CRS: WGS84 (EPSG:4326)
- Method: Coordinate transformation via pyproj Transformer
Vertical Datum¶
- Model reference: Mean Sea Level (MSL)
- Vertical datum: NAVD88 (North American Vertical Datum of 1988)
- Convention: Sea surface elevation (\(\zeta\)) is positive upward relative to NAVD88; bathymetry (\(h\)) is positive downward below NAVD88