2018 - 2019 NOAA NGS Topobathy Lidar: Trappe to Toddville, MD Point Cloud files with Orthometric Vertical Datum North American Vertical Datum of 1988 (NAVD88) using GEOID18

Below are links to the files that make up the 2018 - 2019 NOAA NGS Topobathy Lidar: Trappe to Toddville, MD dataset in an orthometric vertical datum North American Vertical Datum of 1988 (NAVD88) using GEOID18. This HTML file is here to emulate the access you would have gotten through an ftp site. The files containing geospatial indices, metadata, etc., are listed first, followed by the files. To download in bulk, it is suggested you use a program such as wget (example below). The geospatial index file in shapefile format also has a URL attribute that some GIS programs can use to download files. You can also subset the data, make derived products, and change projection, datum, etc., using the Digital Coast Data Access Viewer (add to cart, the link to bulk download or LAZ fmt will take you here).

The files are in LAZ format, a lossless compressed version of the ASPRS LAS format. The compression and decompression is done with the free and open source 'laszip' program available at https://laszip.org. This is not the same as the more general zip format. Many geospatial programs will read LAZ files natively and decompression is often not necessary. There is a list of software with native support on the laszip site. This data is LAS 1.4 format compressed using laszip in native mode. You'll need laszip version 170330 or higher (or tools compiled with at least that version of laszip) to read it.

There are many download managers you can use to get all the data. An example is the uGet program using the list of URLs in file urllist9298.txt. Several posts on the GeoZone blog provide help with downloading, including:

• Using uGet to download bulk lidar
• Downloading a subset of files based on a polygon
• Downloading on Windows without additional programs

The total size to download all the files is 149G. There are 2909 LAZ files and the summary class table is:

Class Number	Class Name	Points
1	Unclassified	15512906389
2	Ground	1988848446
7	Low Point (noise)	283586881
40	Bathymetric point	594377914
43	Submerged Object	19698
45	Water column	15368864492

Georeferencing Note

You may find the georeferencing on the files refers to generic NAD83 (EPSG code 4269). All files, with the exception of the few in WGS84, are in a more recent realization of NAD83 such as NAD83(CORS96), NAD83(HARN), NAD83(NSRS2007), or NAD83(2011).

Cloud Access

Meta Info

Tile Index: tileindex.zip (Shapefile)
                2018_ngs_topobath_trappeMD_index.gpkg (GeoPackage)
Metadata: 2018_ngs_topobath_trappeMD_metadata.xml
Metadata: 2018_ngs_topobath_trappeMD_metadata.html
XYZ range table: 2018_ngs_topobath_trappeMD_minmax.csv
README: 0README.txt (contains similar information to above)
URL List: urllist9298.txt is a list of all the URLs for batch downloading.

Supplemental Info

Point Clouds

This page is owned by the NOAA Office for Coastal Management and was created by an automated script on Mon Dec 20 18:30:30 EST 2021