NOAA S-57 chart cell
Approaches to San Francisco Bay - Seaward of Half Moon Bay, CA
US4CA1AI
- Usage band
- Approach · code 4
- Current edition
- 1.0
- Features
- 64
- S-57 layers
- 25
- Published
- Jan 16, 2026
- Manifest updated
- Jun 22, 2026, 2:51 PM UTC
Coverage
- North
- 37.50000° N
- South
- 37.20000° N
- West
- 123.00000° W
- East
- 122.70000° W
- Center
- 37.35000° N, 122.85000° W
- Bounds area
- 258 sq nm
- Feature density
- 0.2481 / sq nm
Chart Statistics
20 largest layers shown
- Average features per layer
- 2.6
- Smallest layer
- 1
- Largest layer
- 14
- Area sq km
- 885
- Features per sq km
- 0.07235
- SBDARE Seabed area 14
- M_QUAL Data quality 9
- SOUNDG Sounding 7
- DEPCNT Depth contour 6
- DEPARE Depth area 4
- CTNARE Caution area 2
- RESARE 2
- SEAARE Sea area 2
- TESARE 2
- BOYSPP Special purpose buoy 1
- C_AGGR 1
- CONZNE 1
- COSARE 1
- DMPGRD 1
- EXEZNE 1
- LIGHTS Light 1
- M_COVR Coverage 1
- M_NPUB 1
- M_NSYS 1
- MAGVAR Magnetic variation 1
Nearby Chart Cells
Approach usage band
Current Edition Files
The NOAA ZIP archive is the upstream source for this chart cell; the other files are Open Ships generated derivatives for web and GIS use.
- Original NOAA ZIP archive https://www.charts.noaa.gov/ENCs/US4CA1AI.zip
- S-57 cell https://charts.openships.ai/noaa/s57/approach/US4CA1AI/1.0/US4CA1AI.000
- GeoJSON https://charts.openships.ai/noaa/s57/approach/US4CA1AI/1.0/US4CA1AI.geojson
- GeoParquet https://charts.openships.ai/noaa/s57/approach/US4CA1AI/1.0/US4CA1AI.parquet
- Metadata JSON https://charts.openships.ai/noaa/s57/approach/US4CA1AI/1.0/metadata.json
Editions
| Edition | Published | Metadata |
|---|---|---|
| 1.0 | Jan 16, 2026 | metadata.json |