NOAA S-57 chart cell
Mississippi River, Port Allen, and Gulf Intracoastal Waterway Alternate Route
US4LA1II
- Usage band
- Approach · code 4
- Current edition
- 3.1
- Features
- 663
- S-57 layers
- 52
- Published
- Jan 13, 2026
- Manifest updated
- Jun 22, 2026, 2:51 PM UTC
Coverage
- North
- 30.60000° N
- South
- 30.30000° N
- West
- 91.50000° W
- East
- 91.20000° W
- Center
- 30.45000° N, 91.35000° W
- Bounds area
- 280 sq nm
- Feature density
- 2.3705 / sq nm
Chart Statistics
20 largest layers shown
- Average features per layer
- 12.8
- Smallest layer
- 1
- Largest layer
- 76
- Area sq km
- 959
- Features per sq km
- 0.69113
- DEPCNT Depth contour 76
- DEPARE Depth area 75
- COALNE Coastline 60
- SLCONS Shoreline construction 51
- ROADWY 45
- SOUNDG Sounding 31
- LIGHTS Light 21
- OBSTRN Obstruction 19
- PIPARE 19
- BUISGL 17
- DAYMAR 16
- BUAARE 15
- LNDRGN Land region 15
- RIVERS River 15
- SILTNK 15
- BCNLAT Lateral beacon 12
- M_QUAL Data quality 12
- MORFAC 11
- LNDMRK 10
- RESARE 10
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/US4LA1II.zip
- S-57 base cell https://charts.openships.ai/noaa/s57/approach/US4LA1II/3.1/US4LA1II.000
- S-57 update 001 https://charts.openships.ai/noaa/s57/approach/US4LA1II/3.1/US4LA1II.001
- GeoJSON https://charts.openships.ai/noaa/s57/approach/US4LA1II/3.1/US4LA1II.geojson
- GeoParquet https://charts.openships.ai/noaa/s57/approach/US4LA1II/3.1/US4LA1II.parquet
- Metadata JSON https://charts.openships.ai/noaa/s57/approach/US4LA1II/3.1/metadata.json
Editions
| Edition | Published | Metadata |
|---|---|---|
| 3.1 | Jan 13, 2026 | metadata.json |