2017 OLC Lidar: Grass Valley, OR

Create custom data files by choosing data area, product type, map projection, file format, datum, etc. A new metadata will be produced to reflect your request using this record as a base.

Bulk download of data files in LAZ format, geographic coordinates, orthometric heights. Note that the vertical datum (hence elevations) of the files here are different than described in this document.

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.

This graphic displays the footprint for this lidar data set.

Link to data set report.

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.

This data source was used to populate the lidar point cloud data.

The lidar survey utilized a Leica ALS 80 sensor mounted in a Cessna Grand Caravan. The system settings were developed to yield points with an average native density of greater than 8 pulses per square meter over terrestrial surfaces. The study area was surveyed with opposing flight line side-lap of greater than 60 percent with at least 100 percent overlap to reduce laser shadowing and increase surface laser painting. The system allows up to four range measurements per pulse, and all discernible laser returns were processed for the output data set.

Ground control points and ground survey points were collected using real time kinematic (RTK), post-processed kinematic (PPK), and fast static (FS) survey techniques. For RTK surveys, a base receiver was positioned at a nearby monument to broadcast a kinematic correction to a roving receiver, for PPK and FS surveys, however, these corrections were post-processed. RTK and PPK surveys recorded observations for a minimum of 5 seconds, while FS surveys recorded observations for up to 15 minutes on each GCP/GSP in order to support longer baselines for post-processing. All GCP and GSP measurements were made during periods with a Position Dilution of Precision (PDOP) no greater than 3.0 and in view of at least 6 satellites for both receivers. Relative errors for the position were required to be less than 1.5 centimeters horizontal and 2.0 centimeters vertical in order to be accepted.

In order to facilitate comparisons with high quality lidar data, GCP and GSP measurements were not taken on highly reflective surfaces such as center line stripes of lane markings on roads. GCPs and GSPs were taken no closer than one meter to any nearby terrain breaks such as road edges or drop offs. GCPs and GSPs were collected within as many flight lines as possible: however, the distribution depended on ground access constraints and may not be equitably distributed throughout the study area.

The NOAA Office for Coastal Management (OCM) received 854 lidar point cloud files in laz format from DOGAMI. The files contained lidar elevation and intensity measurements. The data were in Oregon Lambert (NAD83 2011), international feet coordinates and NAVD88 (Geoid12B) elevations in international feet. 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 Geoid 12B model, to convert from Oregon Lambert (NAD83 2011), international feet coordinates to geographic coordinates, to convert from vertical units feet to meters, to assign the geokeys, to sort the data by gps time, and zip the data to database and to http.