Snow-Off Digital Terrain Model (DTM) shaded relief from 2010 LiDAR Niwot Ridge LTER Project Area, Colorado

This 1m Digital Terrain Model (DTM) shaded relief is a snow-off DTM derived from
bare-ground Light Detection and Ranging (LiDAR) point cloud data from August 2010
for the Boulder Creek Critical Zone Observatory (CZO), near Boulder Colorado. This
dataset is better suited for derived layers such as slope angle, aspect, and
contours. The DTM was created from 1,375 LiDAR point cloud tiles subsampled from 10
points/m2 to 1-meter postings, acquired by the National Center for Airborne Laser
Mapping (NCALM) project. This data was collected in collaboration between the
Boulder Creek CZO and NCALM, both funded by the National Science Foundation (NSF).
The DTM has the functionality of a map layer for use in Geographic Information
Systems (GIS) or remote sensing software. Total area imaged is 598.92 km^2. The
LiDAR point cloud data was acquired with an Optech Gemini Airborne Laser Terrain
Mapper (ALTM) and mounted in a Piper Twin PA-31 Chieftain with Inertial Measurement
Unit (IMU) at a flying height of 600 m. Data from four GPS (Global Positioning
System) ground stations were used for aircraft trajectory determination. The
continuous DTM surface was created by mosaicing and then kriging 0.5 x 1 km LiDAR
point cloud LAS-formated tiles using Golden Software's Surfer 8 Kriging algorithm.
Horizontal accuracy is at least, but usually better than, 11 cm RMSE at 1 sigma and
vertical accuracy is 5-30 cm RMSE at 1 sigma. The layer is available in IMAGINE
format approx. 4 GB of data. It has a UTM zone 13 projection, with a NAD83 horizonal
datum and a NAVD88 vertical datum, with FGDC-compliant metadata. A shaded relief
model was also generated. A similar layer, the Digital Surface Model (DSM), is a
first-stop elevation layer. Accessory layers consist of index map layers for point
cloud tiles and flight lines, each with detailed attribute information such as
acquisition date and tile file name. The DTM is available through an unrestricted
public license. Other LiDAR DSMs, DTMs, and point cloud data available in this
series include snow-on data for 2010. Together, the LiDAR DEMs and point cloud data
will be of interest to land managers, scientists, and others for study of
topography, snow, ecosystems, and environmental change. NOTE: This EML metadata file
does not contain important geospatial data processing information. Before using any
NWT LTER geospatial data read the arcgis metadata XML file in either ISO or FGDC
compliant format, using ArcGIS software (ArcCatalog > description), or by viewing
the .xml file provided with the geospatial dataset.