Aspect (in radians) grid from Bare earth digital elevation model (DEM) from 2008 LiDAR, Andrews Experimental Forest

Raster Dataset

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Tags
topography, HJ Andrews Experimental Forest, Landscape Ecology, Oregon, geology, Blue River Watershed, LiDAR, digital elevation model (DEM), Willamette Basin


Summary

The base or bare-earth DEM values were used to calculate the aspect of the study area. Values are in meters. The final product is in ESRI GRID digital format, with a 1 meter cell size resolution. Each cell in the GRID has a value that represents the modeled aspect at that location, in radians with low value of 0 and high value of 360 degrees. The purpose of the data is to provide users with a very accurate aspect calculation for each grid cell. The data are suitable for creating visualizations, for models that require aspect as an input, determining suitability for on the ground actiivites, and for descriptions of specific sites that require an aspect value.

Description

Watershed Sciences, Inc. (WS) collected Light Detection and Ranging (LiDAR) data from HJ Andrews and the Willamette National Forest (NF) on August 10th and 11th 2008. Total area for this AOI is 17,705 acres. The total area of delivered LiDAR including 100 m buffer is 19,493 acres. This raster contains an computer generated aspect model of the LiDAR (the bare-earth Digital Elevation Model .

Credits

Use limitations

See access and use constraints information.

Extent

West  -122.277460    East  -122.099580
North  44.282961    South  44.196797

Scale Range
Maximum (zoomed in)  1:5,000
Minimum (zoomed out)  1:50,000

ArcGIS Metadata ▼►

Topics and Keywords  ▼►

Themes or categories of the resource  elevation, environment


* Content type  Downloadable Data


Place keywords  HJ Andrews Experimental Forest, Oregon, Blue River Watershed, Willamette Basin

Theme keywords  topography, Landscape Ecology, geology, LiDAR, digital elevation model (DEM), vegetation

Thesaurus  ▼►
Title Andrews Forest LTER Thesaurus


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Citation  ▼►

Title Aspect (in radians) grid from Bare earth digital elevation model (DEM) from 2008 LiDAR, Andrews Experimental Forest
Creation date 2008-11-14 00:00:00
Publication date 2012-11-21 00:00:00


Edition 1


Presentation formats  digital map
FGDC geospatial presentation format  raster digital data


Other citation details gi01005


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Citation Contacts  ▼►

Responsible party 
Organization's name Watershed Sciences
Contact's role  originator


Responsible party 
Organization's name Forest Science Data Bank
Contact's role  publisher


Contact information  ▼►
Address 
Delivery point Corvallis, OR

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Resource Details  ▼►

Dataset languages  English (UNITED STATES)
Dataset character set  utf8 - 8 bit UCS Transfer Format


Status  completed
Spatial representation type  grid


Spatial resolution 
Dataset's scale 
Scale denominator 1

Ground sample distance 
Precision of spatial data 1 m (meter)


* Processing environment Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.1.1.3143


ArcGIS item properties 
* Name hja_aspect
* Location file://J:\hja83\lidar\hja_aspect
* Access protocol Local Area Network

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Extents  ▼►

Extent 
Description
The LiDAR was flown on August 10th and 11, 2008 and processed data was delivered
                on November 14th, 2008.
Temporal extent 
Beginning date 2008-08-10 00:00:00
Ending date 2008-08-11 00:00:00

Extent 
Geographic extent 
Bounding rectangle 
Extent type  Extent used for searching
* West longitude -122.277460
* East longitude -122.099580
* North latitude 44.282961
* South latitude 44.196797
* Extent contains the resource Yes

Extent in the item's coordinate system 
* West longitude 557736.000000
* East longitude 571848.000000
* South latitude 4894124.000000
* North latitude 4903556.000000
* Extent contains the resource Yes

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Resource Points of Contact  ▼►

Point of contact 
Individual's name Theresa Valentine
Organization's name Corvallis Forest Science Laboratory
Contact's position Spatial Information Manager
Contact's role  point of contact


Contact information  ▼►
Phone 
Voice 541-750-7333
Fax 541-750-7760

Address 
Type both
Delivery point 3200 SW Jefferson Way
City Corvallis
Administrative area Oregon
Postal code 97332
Country US
e-mail address tvalentine@fs.fed.us or theresa.valentine@orst.edu

Hours of service m-f 0800-1630
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Resource Maintenance  ▼►

Resource maintenance 
Update frequency  as needed


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Resource Constraints  ▼►

Constraints 
Limitations of use
See access and use constraints information.
Security constraints 
Classification  unclassified
Classification system USDA Forest Service


Additional restrictions No restrictions


Legal constraints 
Limitations of use
no legal constraints on use of this data. We ask that the following
                    Acknowledgements be made:
                    http://andrewsforest.oregonstate.edu/lter/acknowledgements.cfm
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Spatial Reference  ▼►

ArcGIS coordinate system 
* Type Projected
* Geographic coordinate reference GCS_North_American_1983
* Projection NAD_1983_UTM_Zone_10N
* Coordinate reference details 
Projected coordinate system 
Well-known identifier 26910
X origin -5120900
Y origin -9998100
XY scale 450445547.3910538
Z origin -100000
Z scale 10000
M origin -100000
M scale 10000
XY tolerance 0.001
Z tolerance 0.001
M tolerance 0.001
High precision true
Latest well-known identifier 26910
Well-known text PROJCS["NAD_1983_UTM_Zone_10N",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-123.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0],AUTHORITY["EPSG",26910]]

Reference system identifier 
Value 26910
* Codespace EPSG
* Version 7.11.2


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Spatial Data Properties  ▼►

Georectified Grid  ▼►
* Number of dimensions 2


Axis dimensions properties 
Dimension type  column (x-axis)
* Dimension size 14112
* Resolution  1.000000 Meter

Axis dimensions properties 
Dimension type  row (y-axis)
* Dimension size 9432
* Resolution  1.000000 Meter

* Cell geometry  area
* Point in pixel  center


* Transformation parameters are available Yes


* Check points are available No


Corner points 
* Point 557736.000000 4894124.000000
* Point 557736.000000 4903556.000000
* Point 571848.000000 4903556.000000
* Point 571848.000000 4894124.000000

* Center point 564792.000000 4898840.000000


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Grid  ▼►
Number of dimensions 2


Axis dimensions properties 
Dimension type  row (y-axis)
Dimension size 9432
Resolution  1 m (meter)

Axis dimensions properties 
Dimension type  column (x-axis)
Dimension size 14112
Resolution  1 m (meter)

Cell geometry  area


Transformation parameters are available No


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ArcGIS Raster Properties 
▼►
General Information 
* Pixel depth 32
* Compression type RLE
* Number of bands 1
* Raster format GRID
* Source type continuous
* Pixel type floating point
* No data value -3.4028235e+038
* Has colormap No
* Has pyramids Yes


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Spatial Data Content  ▼►

Image Description 
* Type of information  physical measurement
Attribute described by cell values aspect in radians


Band information 
* Description hja_aspect
* Maximum value 359.999817
* Minimum value -1.000000
Units 
Symbol m

* Number of bits per value 32


Image quality code 
Value none


Processing level code 
Value none


Triangulation has been performed No
Radiometric calibration is available No
Camera calibration is available No
Film distortion information is available No
Lens distortion information is available No


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Data Quality  ▼►

Scope of quality information  ▼►
Resource level  dataset
Scope description 
Dataset HJA LiDAR flight of 2008

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Data quality report - Completeness omission  ▼►
Test date 2008-11-12 00:00:00


Measure description see description in on-line documentation


Standard procedure identifier 
Value none


Evaluation type  direct internal
Evaluation method see description in on-line documentation
Evaluation procedure  ▼►
Title LiDAR Remote Sensing Data Collection: HJ Andrews and Willamette NF
Creation date 2008-11-14 00:00:00
Publication date 2008-11-14 00:00:00


Edition 1
Edition date 2008-11-14


Resource location online 
Location http://andrewsforest.oregonstate.edu/lter/data/aerial/hj_andrews_report.pdf
Access protocol pdf
Function performed  download

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Data quality report - Conceptual consistency  ▼►
Dimension horizontal


Measure description see description in arcgis on-line


Standard procedure identifier 
Value aspect


Evaluation type  direct internal
Evaluation method from comuter program
Evaluation procedure  ▼►
Title arcgis help
Creation date 2013-02-04 00:00:00


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Lineage  ▼►

Process step 
▼►
When the process occurred 2008-09-01 00:00:00
Description Simultaneous with the airborne data collection mission, we conducted multiple static (1 Hz recording frequency) ground surveys over monuments with known coordinates (Table 1). Indexed by time, these GPS data are used to correct the continuous onboard measurements of aircraft position recorded throughout the mission. Multiple sessions were processed over the same monument to confirm antenna height measurements and reported position accuracy. After the airborne survey, these static GPS data were then processed using triangulation with Continuously Operating Reference Stations (CORS) stations, and checked against the Online Positioning User Service (OPUS2) to quantify daily variance. Controls were located within 13 nautical miles of the mission area(s).


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Process step 
▼►
When the process occurred 2008-10-01 00:00:00
Description 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. 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 (< 500 MB). Flightlines and LiDAR data were then reviewed to ensure complete coverage of the study area and positional accuracy of the laser points. 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. 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. 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 (<1 cm) in relative accuracy. 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.


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Process step 
▼►
When the process occurred 2008-10-16 00:00:00
Description Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. Software: Waypoint GPS v.7.60 2. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with attitude data (sensor heading, position, and attitude are calculated throughout the survey). Software: IPAS v.1.4 3. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las (ASPRS v1.1) format. Software: ALS Post Processing Software 4. Import raw laser points into subset bins (less than 500 MB, to accommodate file size constraints in processing software). Perform manual relative accuracy calibration and filter for pits/birds. Classify ground points for individual flight lines (to be used for relative accuracy testing and calibration). Software: TerraScan v.7.012 5. Test relative accuracy using ground classified points per each flight line. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Perform calibrations on ground classified points from paired flight lines. Every flight line is used for relative accuracy calibration. Software: TerraMatch v.7.004 6. Import position and attitude data. Classify ground and non-ground points. Assess statistical absolute accuracy via direct comparisons of ground classified points to ground RTK survey data. Convert data to orthometric elevations (NAVD88) by applying a Geoid03 correction. Create ground model as a triangulated surface and export as ArcInfo ASCII grids at the specified pixel resolution.


Process contact 
Organization's name Watershed Sciences
Contact's role  originator


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Process step 
▼►
When the process occurred 2008-10-16 00:00:00
Description The LiDAR survey uses a Leica ALS50 Phase II laser system. For the HJ Andrews and Willamette NF study areas, the sensor scan angle was ±14o from nadir1 with a pulse rate designed to yield an average native density (number of pulses emitted by the laser system) of 8 points per square meter over terrestrial surfaces. All study areas were surveyed with an opposing flight line side-lap of =50% (=100% overlap) to reduce laser shadowing and increase surface laser painting. The Leica ALS50 Phase II system allows up to four range measurements (returns) per pulse, and all discernable laser returns were processed for the output dataset. It is not uncommon for some types of surfaces (e.g. dense vegetation or water) to return fewer pulses than the laser originally emitted. These discrepancies between ‘native’ and ‘delivered’ density will vary depending on terrain, land cover and the prevalence of water bodies. To accurately solve for laser point position (geographic coordinates x, y, z), the positional coordinates of the airborne sensor and the attitude of the aircraft were recorded continuously throughout the LiDAR data collection mission. Aircraft position was measured twice per second (2 Hz) by an onboard differential GPS unit. Aircraft attitude was measured 200 times per second (200 Hz) as pitch, roll and yaw (heading) from an onboard inertial measurement unit (IMU). To allow for post-processing correction and calibration, aircraft/sensor position and attitude data are indexed by GPS time


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Process step 
▼►
When the process occurred 2009-03-23 00:00:00
Description The bare-earth DEM was used to calculate an aspect grid, using commands in ArcGIS desktop version 10.0


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Geoprocessing history  ▼►

Process 
Process name 
Date 2009-03-23 10:13:50
Tool location C:\Program Files\ArcGIS\ArcToolbox\Toolboxes\Spatial Analyst Tools.tbx\Aspect
Command issued
Aspect P:\HJA_LIDAR\LIDAR\Rasters\Bare_Earth\hja_be P:\HJA_LIDAR\LIDAR\Rasters\Bare_Earth\hja_aspect
Include in lineage when exporting metadata No


Process 
Process name 
Date 2009-03-27 10:10:04
Tool location C:\Program Files\ArcGIS\ArcToolbox\Toolboxes\Data Management Tools.tbx\CalculateStatistics
Command issued
CalculateStatistics P:\HJA_LIDAR\LIDAR\Rasters\Bare_Earth\hja_aspect 1 1 # P:\HJA_LIDAR\LIDAR\Rasters\Bare_Earth\hja_aspect
Include in lineage when exporting metadata No


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Distribution  ▼►

Distributor  ▼►
Contact information 
Individual's name Theresa Valentine
Organization's name Corvallis Forest Science Laboratory
Contact's position Spatial Information Manger
Contact's role  distributor


Contact information  ▼►
Phone 
Voice 541-750-7333
Fax 541-758-7760

Address 
Type both
Delivery point 3200 SW Jefferson Way
City Corvallis
Administrative area OR
Postal code 97332
Country US
e-mail address tvalentine@fs.fed.us or theresa.valentine@orst.edu

Hours of service m-f 8:00am-4:30pm
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Ordering process 
Instructions
Call contact person for instructions and costs.

Ordering process 
Terms and fees none
Turnaround time as time permits
Instructions
Obtain information off of WWW site, call contact person for special
                    requests.

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Distribution format 
Version ArcGIS 10.0
* Name Raster Dataset


Transfer options 
Online source 
Location http://andrewsforest.oregonstate.edu/data/studies/spatialdata/gi01005.zip
Function performed  download

Medium of distribution 
Medium name  hard disk


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Fields  ▼►

Details for object hja_aspect  ▼►
Type raster
Definition
each cell represents a calculated aspect value.
Definition source
Watershed Sciences


Field value
  ▼►
Data type floating point
Width 10
Field description
aspect of the cell, value is in radians with a range of values from 0 to 360 degrees.
Description source
Watershed Sciences documentation
Range of values 
Minimum value 0
Maximum value 360
Units of measure radian

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References  ▼►

Aggregate Information 
Association type  cross reference


Aggregate resource name  ▼►
Title LiDAR Remote Sensing Data Collection HJ Andrews and Willamette National Forest
Creation date 2008-11-14 00:00:00
Publication date 2012-11-14 00:00:00


Edition 1


Presentation formats  hardcopy document
FGDC geospatial presentation format  document


Responsible party 
Organization's name Watershed Sciences
Contact's role  originator


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Metadata Details  ▼►

* Metadata language English (UNITED STATES)
Metadata character set  utf8 - 8 bit UCS Transfer Format


Scope of the data described by the metadata  dataset
Scope name  * dataset


* Last update 2013-06-13


ArcGIS metadata properties
Metadata format ArcGIS 1.0
Metadata style FGDC CSDGM Metadata
Standard or profile used to edit metadata FGDC


Created in ArcGIS for the item 2013-02-04 13:28:19
Last modified in ArcGIS for the item 2013-06-13 16:13:49


Automatic updates
Have been performed Yes
Last update 2013-06-13 16:13:49

Item location history 
Item copied or moved 2013-02-04 13:28:19
From P:\HJA_LIDAR\LIDAR\Rasters\Bare_Earth\hja_aspect
To \\quercus\fordata\oregon\willamette\hja83\lidar\hja_aspect


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Metadata Contacts  ▼►

Metadata contact 
Individual's name Theresa Valentine
Organization's name Corvallis Forest Science Laboratory
Contact's position Spatial Information Manager
Contact's role  point of contact


Contact information  ▼►
Phone 
Voice 541-750-7333
Fax 541-758-7760

Address 
Type both
Delivery point 3200 SW Jefferson Way
City Corvallis
Administrative area Oregon
Postal code 97332
Country US
e-mail address tvalentine@fs.fed.us or theresa.valentine@orst.edu

Hours of service m-f 8:00am-4:00pm
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Metadata Maintenance  ▼►

Maintenance 
Update frequency  as needed


Scope of the updates  feature


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Metadata Constraints  ▼►

Security constraints 
Classification  unclassified


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Thumbnail and Enclosures  ▼►

Thumbnail 
Thumbnail type  JPG

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FGDC Metadata (read-only) ▼►

Entities and Attributes  ▼►

Detailed Description
Entity Type
Entity Type Label hja_aspect
Entity Type Definition
each cell represents a calculated aspect value.
Entity Type Definition Source Watershed Sciences

Attribute
Attribute Label value
Attribute Definition
aspect of the cell, value is in radians with a range of values from 0 to 360 degrees.
Attribute Definition Source Watershed Sciences documentation
Attribute Domain Values
Range Domain
Range Domain Minimum 0
Range Domain Maximum 360
Attribute Units of Measure radian

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