2007 Oregon Department of Geology and Mineral Industries (DoGAMI) LiDAR: Northwest
Oregon and Portland Metro Area
Watershed Sciences, Inc. collected Light Detection and Ranging (LiDAR) data for the
Oregon Department of Geology and Mineral Industries (DoGAMI) and the Oregon Department
of Forestry (ODF) between March 15 and November 7 2007. This data set has bare earth
and unclassified points. The dataset encompasses portions of the following counties
in northwest Oregon: Multnomah, Marion, Hood River, Clackamas, Columbia, Washington
and Yamhill. Areas of interest within this data set are the Portland Metro area, Mt.
Hood and Silver Falls State Park. There is approximately 8 points per square meter
over terrestrial surfaces. 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. Lidar intensity values were also collected.
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
Lidar Dataset Supplemental Information
- Oregon Department of Geology and Mineral Industries (DoGAMI)
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| Not planned
||Provide high resolution terrain elevation and land cover elevation data.
||2007-03-15 to 2007-11-07
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Light Detection and Ranging
- Digital Terrain Model
- Elevation data
- Bare earth
- Bare ground
- United States
- Pacific Northwest
- Portland Metro Area
- Marion County
- Clackamas County
- Multnomah County
- Hood River County
- Columbia County
- Washington County
- Yamhill County
- Mt. Hood
- Silver Falls State Park
- Silver Falls
- Williamette Valley
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
- Watershed Sciences, Inc.
- DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department
| Processing Steps
- Acquisition. The LiDAR data was collected between March 15 and November 11, 2007.
The survey used a Leica ALS50 Pase II laser system mounted in a Cessna Caravan 208,
and an Optech 3100 laser system mounted in a Cessna Caravan 208. 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 ALS Post Processor software, IPAS Pro GPS/INS software,
REALM survey suite, and PosPac software, 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 ALS postprocessing software and 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 output as laser points, TINed and GRIDed surfaces.
- 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 and Oregon State Plane projections, and NAVD88 Geoid 03 vertical datum. CSC
performed the following processing to the data to make it available within the LDART
Retrieval Tool (LDART): 1. The data were converted from Lambert Conformal Conic and
Oregon State Plane 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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