Data

New Data – Topobathy Lidar bare earth DEMs for Southern RI

Between July and August of 2014 the National Oceanic and Atmospheric Administration (NOAA) National Geodetic Survey (NGS) collected topobathy LiDAR for 2,775 miles of the Atlantic Coast from Rhode Island to South Carolina. This provides coverage of areas highly damaged during the landfall of Hurricane Sandy in late October 2012. In Rhode Island, this project covered a total area of 205 square miles along the south coast, from Westerly to Narragansett. These data have been available for download from RIGIS as raw, vendor-created LAS files since the inception of the new website, however I am happy to announce the release of bare earth Digital Elevation Models created and tiled by RIGIS.


For those of you not familiar with topobathy LiDAR, here is some background information on how it is collected, and some of the ways it can be used:

As most of you probably know, LiDAR, or Light Detection and Ranging, is a method used to remotely study the surface of the earth. LiDAR data is most commonly collected through the utilization of airplanes and helicopters; these carry the instrumentation necessary to collect these data. This specialized instrumentation consists of a laser, a scanner and a GPS receiver. This equipment collects information about the surface of the earth through a series of pulses of light, creating a three-dimensional representation of the surface.

Airborne topobathy LiDAR is collected in a similar manner to the traditional terrestrial LiDAR described above, however in addition to the near-infrared wavelength (1000 – 1500 µm) laser, a blue-green wavelength ( 532 µm) laser is utilized.  This blue-green wavelength laser allows for penetration through the water column.

This penetration of the water column allows data users to visulaize near-shore bathymetric environments. This can be great for use in a variety of modeling applications such as inundation modeling, sea level rise modeling, shoreline delineation, habitat mapping, inland watershed applications, restoration planning and coastal geomorphological analyses to name a few.


Topobathy LiDAR offers a seamless transition between land and submerged areas, something traditional LiDAR lacks. Although this topobathy does not provide full coverage of the Rhode Island coastline, I hope that the RIGIS community finds these data useful. These data are offered as tiled GeoTIFF images, in the Rhode Island State Plane Feet coordinate system, with both horizontal and vertical units of feet. Get started by downloading it here!

Above is a sample of the NOAA Topobathy LiDAR for Rhode Island. This is just a mosaic dataset of all individual tiles available for download from the link above!

Above is a sample of the NOAA Topobathy LiDAR for Rhode Island. This is just a mosaic dataset of all individual tiles available for download from the link above! 


For additional information on how to develop your own topobathy DEM using the raw LAS files we offer, visit this blog posting from the Environmental Data Center at URI.

To learn how to create beautiful visualizations with topobathy DEMs, click here.