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Short Citation:
OCM Partners, 2024: 2008 USDA Forest Service Lidar: Sandy River Study Area,

Item Identification

Title: 2008 USDA Forest Service Lidar: Sandy River Study Area
Short Name: usda2008_or_sandy_river_m1432_metadata
Status: Completed
Publication Date: 2012

Watershed Sciences, Inc. collected Light Detection and Ranging (LiDAR) data for the Sandy River study area in collaboration

with the USDA Forest Service. The areas for LiDAR collection have been designed as part of a collaborative effort of state,

federal, and local agencies in order to meet a wide range of project goals.

This LiDAR data set was collected Sept 29 - Oct 1, 2008 and falls mainly in Multnomah County, but also in small portions

of Clark and Clackamas Counties, Oregon. This data set consists of bare earth and unclassified points. The average pulse density

is 8.04 pulses per square meter over terrestrial surfaces. The area of interest (AOI) encompasses approximately 34,021 acres and

the total area flown (TAF) covers 35,873 acres. The TAF acreage is greater than the original AOI acreage due to buffering and

flight planning optimization.

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.

Original contact information:

Contact Name: Ian Madin

Contact Org: DOGAMI

Phone: 971-673-1542



Provide high resolution terrain elevation and land cover elevation data.



Supplemental Information:

The final LiDAR Report for the Sandy River study area may be accessed at:

A footprint of this data set may be viewed in Google Earth at:


Theme Keywords

Thesaurus Keyword
ISO 19115 Topic Category
None Bare earth
None Bare ground
None High-resolution
None Light Detection and Ranging

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Maintenance Frequency: None Planned
Entity Attribute Overview:

Lidar points in LAZ format Classed 1,2

Entity Attribute Detail Citation:


Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of the USDA

Forest Service, the Office for Coastal Management or its partners.

Data Set Credit: USDA Forest Service

Support Roles

Data Steward

CC ID: 690325
Date Effective From: 2012
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


CC ID: 690327
Date Effective From: 2012
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Metadata Contact

CC ID: 690328
Date Effective From: 2012
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202

Point of Contact

CC ID: 690326
Date Effective From: 2012
Date Effective To:
Contact (Organization): NOAA Office for Coastal Management (NOAA/OCM)
Address: 2234 South Hobson Ave
Charleston, SC 29405-2413
Email Address:
Phone: (843) 740-1202


Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1133399
W° Bound: -122.427072
E° Bound: -122.104372
N° Bound: 45.575607
S° Bound: 45.369807

Extent Group 1 / Time Frame 1

CC ID: 1133398
Time Frame Type: Range
Start: 2008-09-29
End: 2008-10-01

Spatial Information

Spatial Representation

Representations Used

Vector: Yes

Access Information

Security Class: Unclassified
Data Access Procedure:

This data can be obtained on-line at the following URL:

This data set is dynamically generated based on user-specified parameters.


Data Access Constraints:


Data Use Constraints:

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no

longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its


Distribution Information

Distribution 1

CC ID: 743011
Download URL:
File Name: Customized Download

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Distribution 2

CC ID: 743012
Download URL:
File Name: Bulk Download

Simple download of data files.



CC ID: 743014
URL Type:
Online Resource


CC ID: 743015
URL Type:
Online Resource


CC ID: 743016
Name: Browse Graphic
URL Type:
Browse Graphic
File Resource Format: kmz

This graphic shows the lidar coverage for the Sandy River Study Area.

Activity Log

Activity Log 1

CC ID: 690351
Activity Date/Time: 2016-05-23

Date that the source FGDC record was last modified.

Activity Log 2

CC ID: 690350
Activity Date/Time: 2017-11-14

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using '' script. Contact Tyler Christensen (NOS) for details.

Activity Log 3

CC ID: 718701
Activity Date/Time: 2018-02-08

Partial upload of Positional Accuracy fields only.

Activity Log 4

CC ID: 743013
Activity Date/Time: 2018-03-13

Partial upload to move data access links to Distribution Info.

Technical Environment


Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog

Data Quality

Horizontal Positional Accuracy:

Not specified in final report, assumed to be 1 m.

Vertical Positional Accuracy:

The Root Mean Square Error (RMSE) of the data is 0.051 meters. Accuracy was assessed using 506 ground survey RTK (real time

kinematic) points. These ground survey points are distributed throughout the Sandy River study area.

The final LiDAR Report for the Sandy River study area may be accessed at:

Completeness Report:

LiDAR data has been collected and processed for all areas within the project study area.

Conceptual Consistency:

LiDAR flight lines have been examined to ensure that there is at least 50% sidelap, that there are no gaps between flightlines, and

that overlapping flightlines have consistent elevation values. Shaded relief images have been visually inspected for data errors such as

pits, border artifacts, gaps, and shifting.


Process Steps

Process Step 1

CC ID: 1133395

No metadata was provided to NOAA OCM with this data set. The following process step is derived from the Watershed Sciences, Inc.

lidar report. This report may be accessed at:


1. The lidar data were collected between Sept 29 - Oct 1, 2008.

2. The survey used a Leica ALS50 Phase II sensor.

3. Near nadir scan angles were used to increase penetration of vegetation to ground surfaces.

4. Ground level GPS and aircraft IMU were collected during the flight.


1. Laser point coordinates were computed using the REALM software based on independent data from the LiDAR system

(pulse time, scan angle), and aircraft trajectory data (SBET). Laser point returns (first through fourth) were assigned

an associated (x, y, z) coordinate along with unique intensity values (0-255). The data were output into large LAS v. 1.1

files; each point maintains the corresponding scan angle, return number (echo), intensity, and x, y, z (easting, northing,

and elevation) information.

2. These initial laser point files were too large for subsequent processing. To facilitate laser point processing, bins

(polygons) were created to divide the dataset into manageable sizes (less than 500 MB). Flightlines and LiDAR data were then

reviewed to ensure complete coverage of the study area and positional accuracy of the laser points.

3. Laser point data were imported into processing bins in TerraScan, and manual calibration was performed to assess

the system offsets for pitch, roll, heading and scale (mirror flex). Using a geometric relationship developed by

Watershed Sciences, each of these offsets was resolved and corrected if necessary.

4. LiDAR points were then filtered for noise, pits (artificial low points) and birds (true birds as well as erroneously

high points) by screening for absolute elevation limits, isolated points and height above ground. Each bin was then

manually inspected for remaining pits and birds and spurious points were removed. In a bin containing approximately

7.5 - 9.0 million points, an average of 50 - 100 points are typically found to be artificially low or high. Common sources

of non-terrestrial returns are clouds, birds, vapor, haze, decks, brush piles, etc.

5. Internal calibration was refined using TerraMatch. Points from overlapping lines were tested for internal consistency

and final adjustments were made for system misalignments (i.e., pitch, roll, heading offsets and scale). Automated sensor

attitude and scale corrections yielded 3-5 cm improvements in the relative accuracy. Once system misalignments were

corrected, vertical GPS drift was then resolved and removed per flight line, yielding a slight improvement (less than 1 cm)

in relative accuracy.

6. The TerraScan software suite is designed specifically for classifying near-ground points (Soininen, 2004). The processing

sequence began by removing all points that were not near the earth based on geometric constraints used to evaluate

multi-return points. The resulting bare earth (ground) model was visually inspected and additional ground point

modeling was performed in site-specific areas to improve ground detail. This manual editing of grounds often occurs

in areas with known ground modeling deficiencies, such as: bedrock outcrops, cliffs, deeply incised stream banks, and

dense vegetation. In some cases, automated ground point classification erroneously included known vegetation

(i.e., understory, low/dense shrubs, etc.). These points were manually reclassified as non-grounds. Ground surface

rasters were developed from triangulated irregular networks (TINs) of ground points.

Process Step 2

CC ID: 1133396

The NOAA Office for Coastal Management (OCM) received the files in las format. The files contained LiDAR

elevation and intensity measurements. The data were in UTM Zone 10 NAD83(CORS96) projection, NAVD88 (Geoid03) vertical datum

and units were in meters. OCM performed the following processing for data storage and Digital Coast provisioning purposes:

1. The data were converted from UTM Zone 10 coordinates to geographic coordinates.

2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid03.

3. The data were sorted by time and zipped to laz format.

Process Date/Time: 2012-12-01 00:00:00

Catalog Details

Catalog Item ID: 50097
GUID: gov.noaa.nmfs.inport:50097
Metadata Record Created By: Anne Ball
Metadata Record Created: 2017-11-15 15:24+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2022-03-16
Owner Org: OCMP
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16