2007 Oregon Parks and Recreation Department Silver Falls State Park Lidar
The dataset represents the Lidar elevations for Silver Falls State Park in Marion
County, Oregon. The LiDAR data was collected during March 2007. This was a leaf-off
condition. The lidar data are multiple return and bare earth classified. An Optech
3100 LiDAR system was mounted in a fixed-wing aircraft and flown 900 meters above
ground level (AGL). A pulse repetition frequency (PRF) of 71 kHz with at least 100%
overlap (minimum 50% side-lap) was used. Greater than 8 points per square meter and
near nadir scan angles were used to increase penetration of vegetation to ground surfaces.
Ground level GPS and aircraft IMU were collected during the flight. In some areas
of heavy vegetation or forest cover, there may be relatively few ground points in
the LiDAR data. Elevation values for open water surfaces are not valid elevation values
because few LiDAR points are returned from water surfaces. Watershed Sciences, Inc.
collected the LiDAR and created this data set for Oregon Parks and Recreation.
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
Oregon Department of Geology and Mineral Industries (DOGAMI)
- Oregon Parks and Recreation Department
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| Not planned
||Provide high resolution terrain elevation and land cover elevation data.
|| Unknown to Unknown
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Light Detection and Ranging
- Digital Terrain Model
- Oregon Parks and Recreation
- Elevation data
- Bare earth
- Bare ground
- United States
- Marion County
- Silver Falls State Park
- Pacific Northwest
- Willamette Valley
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
- DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department
| Processing Steps
- Acquisition. The LiDAR data was collected during March 2007. This was a leaf-off condition.
An Optech 3100 LiDAR system was mounted in a fixed-wing aircraft and flown 900 meters
above ground level (AGL). A pulse repetition frequency (PRF) of 71 kHz with at least
100% overlap (minimum 50% side-lap) was used. Greater than 8 points per square meter
and near nadir scan angles were used to increase penetration of vegetation to ground
surfaces. Ground level GPS and aircraft IMU were collected during the flight.
- Processing. 1. Flight lines and data were reviewed to ensure complete coverage of
the study area and positional accuracy of the laser points. 2. Laser point return
coordinates were computed using the REALM survey suite and PosPac based on independent
data from the LiDAR system, IMU, and aircraft. 3. The raw LiDAR file was assembled
into flight lines per return with each point having an associated x, y, and z coordinate.
4. Visual inspection of swath to swath laser point consistencies within the study
area were used to perform manual refinements of system alignment. 5. Custom algorithms
were designed to evaluate points between adjacent flight lines. Automated system alignment
was computed based upon randomly selected swath to swath accuracy measurements that
consider elevation, slope, and intensities. Specifically, refinement in the combination
of system pitch, roll and yaw offset parameters optimize internal consistency. 6.
Noise (e.g., pits and birds) was filtered using REALM software tools based on known
elevation ranges and included the removal of any cycle slips. 7. Using TerraScan and
Microstation, ground classifications utilized custom settings appropriate to the study
area. 8. The corrected and filtered return points were compared to the RTK ground
survey points collected to verify the vertical and horizontal accuracies. 9. Points
were broken into processing bins and output areas and output as laser points, TINed
and GRIDed surfaces. Bare earth DEMs meet PSLC specifications.
- The NOAA Coastal Services Center (CSC) received the files in las format. The files
contained Lidar elevation and intensity measurements. The data was in Lambert Conformal
Conic projection and NAVD88 Geoid 03 vertical datum. CSC performed the following processing
to the data to make it available within Digital Coast: 1. The data were converted
from Lambert Conformal Conic coordinates to geographic coordinates. 2. The data were
converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid
03. 3. The LAS data were sorted by latitude and the headers were updated.
- The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are
currently being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS
or LAZ format. The LAS format is an industry standard for LiDAR data developed by
the American Society of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless
compressed version of LAS developed by Martin Isenburg (http://www.laszip.org/). The
data are exclusively in geographic coordinates (either NAD83 or ITRF94). The data
are referenced vertically to the ellipsoid (either GRS80 or ITRF94), allowing for
the ability to apply the most up to date geoid model when transforming to orthometric
Metadata Last Modified: 2013-06-07
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