data.lhzn.io
Static files for the public demos of Long Horizon Observatory software.
This host serves the files that a demo needs and nothing else. It is not a data archive or a data service. Each file belongs to one demo and is removed when that demo no longer uses it. For research or operational use, obtain the data from the original providers listed below, which maintain and version it.
Files
| Path | Demo | Contents | Size |
|---|---|---|---|
/vantagekit/montauk-5m.json/vantagekit/montauk-5m.bin.gz |
vantagekit three.js demo | Topobathymetric elevation of Montauk Point, Long Island, New York: 71.930 to 71.821 W, 41.044 to 41.098 N (9.1 by 6.0 km), 2427 by 1595 cells of 3.8 m, heights −22.5 to 47.4 m NAVD88. | 2.7 MB |
Montauk Point grid
The grid is a fusion of the sources below, made with topobathykit (policy: US Coastal Topobathy Fusion 1.1.0). Shares are fractions of grid cells.
- NOAA National Geodetic Survey topobathy lidar, Long Island Sound, 2023, and the USACE New Jersey and New York DEM, 2020: 49 %.
- NOAA Office of Coast Survey BlueTopo: 42 %. Its contributors here include USACE National Coastal Mapping Program lidar (2017) and NOAA hydrographic surveys H05326, H05344, H06828, H10900, H10984 and H12677. Some BlueTopo cells are interpolated between surveys rather than measured.
- NOAA hydrographic survey BAG grids, H12677 (0.5 and 1 m) and W00352 (3 m), from NOAA NCEI: 8 %.
- NOAA NCEI Continuously Updated DEM (CUDEM), 1/9 arc-second, 2015: 0.7 %.
The JSON file gives the grid geometry, the vertical datum, the per-source shares, the encoding and the SHA-256 of the data file. The data file is gzip-compressed little-endian 16-bit integers in centimetres, rows from north to south and columns from west to east, each row stored as its difference from the row above. To decode: decompress, then add each row to the decoded row above it in 16-bit arithmetic, then multiply by 0.01.
Licence and credit
The elevation data are works of the United States government and are in the public domain in the United States. Credit: NOAA Office of Coast Survey, NOAA National Geodetic Survey, NOAA National Centers for Environmental Information, and the US Army Corps of Engineers. The grid has not been reviewed by these agencies and is not for navigation.
Access
Cross-origin reads are allowed from https://lhzn-io.github.io, where the demos run.
Files are cached for one day.