Snow-Off Digital Terrain Model (DTM) from 2010 LiDAR for the Boulder Creek Critical Zone Observatory (CZO), Colorado

This 1m Digital Terrain Model (DTM) 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.