2010 USFS Lidar: Malheur National Forest (LC West), OR

Malheur National Forest - LC West project area.

Dates of collection.

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Bulk download of lidar files in laz format, geographic coordinates, orthometric heights.

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

Data report

This graphic displays the footprint for this lidar data set.

Link to custom download, from the Data Access Viewer (DAV), the raster Digital Elevation Model (DEM) data that were created from this lidar data set.

Acquisition.

LiDAR data acquisition occurred between July 27 and August 19, 2010. LiDAR acquisition of LC West was performed with an Optech ALTM Orion sensor. Aero-Graphics flew at an average altitude of 3280 ft AGL (above ground level) and made appropriate adjustments to compensate for topographic relief. The PRF (pulse rate frequency) used for collection was 100 kHz, scan frequency of 70 Hz, and scan angle of +/- 11 degrees from the nadir position (full scan angle 22 degrees). The ALTM Orion features roll compensation that adjusts the mirror to maintain the full scan angle integrity in relation to nadir, even when less than perfect weather conditions push the sensor off nadir. Acquisition was performed with a 50% side lap and yielded >12.5 points per square meter throughout the project boundary. The Optech ALTM Orion is capable of receiving up to four range measurements, including 1st, 2nd, 3rd, and last returns for every pulse sent from the system.

LiDAR Processing Workflow and Software

a. Absolute Sensor Calibration. The absolute sensor calibration is defined as the difference in roll, pitch, heading, and scale between the raw laser point cloud from the sensor and surveyed control points on the ground over two separate sites. Software: Dashmap 4.1801; ACalib 1.3.5.7.

b. Kinematic Air Point Processing. Differentially corrected the 1-second airborne GPS positions with ground base stations; combined and refined the GPS positions with 1/200-second IMU (roll-pitch-yaw) data through development of a smoothed best estimate of trajectory (SBET). Software: Applanix POSPac 5.3.3664.28463.

c. Raw LiDAR Point Processing. Combined SBET with raw LiDAR range data; solved real-world position for each laser point; produced point cloud data by flight strip in ASPRS v1.1 .LAS format; output in WGS84 UTM Ellipsoid Heights. Software: LiDAR Mapping Suite 1.0.

d. Relative Calibration. Tested relative accuracy; performed relative calibration by correcting for roll, pitch, heading, and scale discrepancies between adjacent flightlines. Results presented in Section 4.1. Software: LiDAR Mapping Suite 1.0.

e. Tiling & Long/Short Filtering. Cut data into project-specified tiles and filtered out grossly long and short returns. Software: TerraScan 10.011.

f. Classification. Ran classification algorithms on points in each tile; separated into ground, unclassified, high outliers and low outliers; revisited areas not completely classified automatically and manually corrected them. Software: TerraScan 10.011.

g. Absolute Accuracy Assessment. Performed comparative tests that showed Z-differences between each static survey point and the laser point surface. Results presented in Section 4.2. Software: TerraScan 10.001.

h. Datum Transformation. Transformed all .LAS tiles from WGS84 UTM 11N Ellipsoid Heights into NAD83 UTM 11N, adjusted for orthometric heights on NAVD88 (Geoid03). Integrity of the .LAS file format was maintained throughout the process. Software: Blue Marble Desktop 2.1.

i. DEM Creation. Generated 2-meter first-return DEMs and 1-meter ground surface DEMs in ESRI Raster Grid format, tiled according to project specifications. Software: TerraScan 10.011.

j. Intensity Image Creation. Generated 1-meter pixel intensity images in GeoTIFF format, tiled according to project specifications. Software: TerraScan 10.011.

The NOAA Office for Coastal Management (OCM) received 528 lidar point cloud files in laz format from DOGAMI. The files contained lidar elevation and intensity measurements. The data were in UTM Zone 11 NAD83, meters, coordinates and NAVD88 (Geoid03) elevations in meters. The data were classified as: 1-Unclassified, 2-Ground. OCM processed all classifications of points to the Digital Coast Data Access Viewer (DAV). Classes available on the DAV are: 1, 2.

OCM performed the following processing on the data for Digital Coast storage and provisioning purposes:

1. An internal OCM script was run to check the number of points by classification and by flight ID and the gps and intensity ranges.

2. Internal OCM scripts were run on the laz files to convert from orthometric (NAVD88) elevations to ellipsoid elevations using the Geoid03 model, to convert from UTM Zone 11 NAD83 coordinates in meters, to geographic coordinates, to assign the geokeys, to sort the data by gps time, and zip the data to database and to http.