2012-2013 USGS Lidar: Territory of Guam Point Cloud files with Orthometric Vertical Datum Guam Vertical Datum of 2004 (GUVD04) using GEOID12B

Below are links to the files that make up the 2012-2013 USGS Lidar: Territory of Guam dataset in an orthometric vertical datum Guam Vertical Datum of 2004 (GUVD04) using GEOID12B. 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 data are all in geographic coordinates using the North American Datum of 1983 (NAD83). The version of the NAD83 datum may vary slightly, but all are one of the updated realizations such as the High Accuracy Reference Network (HARN), Continuously Operating Reference System of 1996 (CORS96), or National Spatial Reference System of 2007 (NSRS2007), and not the original NAD83(86). This may not be evident in the metadata. Vertical units are meters and all have been converted from NAD83 ellipsoid heights to orthometric Guam Vertical Datum of 2004 (GUVD04) heights using GEOID12B.

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.

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 urllist4939.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 18G. There are 320 LAZ files and the summary class table is:

Class Number	Class Name	Points
1	Unclassified	339540923
2	Ground	1110856672
3	Low Vegetation	1099918221
4	Medium Vegetation	1185817168
5	High Vegetation	955148839
6	Building	79311965
7	Low Point (noise)	73622
9	Water	58706594
10	Ignored Ground (near breakline)	753178

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)
                guam2012_usgs_index.gpkg (GeoPackage)
Metadata: guam2012_usgs_m4939_metadata.html
Metadata: guam2012_usgs_m4939_metadata.xml
Metadata: guam2012_usgs_metadata.xml
Metadata: guam2012_usgs_metadata.html
XYZ range table: guam2012_usgs_m4939_minmax.csv
README: 0README.txt (contains similar information to above)
URL List: urllist4939.txt is a list of all the URLs for batch downloading.

Supplemental Info

Breakline Files

Point Clouds

This page is owned by the NOAA Office for Coastal Management and was created by an automated script on Mon Dec 20 15:48:04 EST 2021