RxCADRE 2008, 2011, and 2012: Lidar data and derived raster products

Metadata:

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Resolution of the percent cover data is 2.5 meters. Lidar intensity values are uncalibrated. The average point density (points per square meter) for 2008, 2011, and 2012 data are 5.06, 4.5, and 5.5, respectively.

For more details on the 2008, 2011, and 2012 lidar surveys see the vendor reports included in the full data package download (\Supplements\*.pdf).

Logical_Consistency_Report:

Raster products were qualitatively checked for 0 or negative heights, or unrealistically high Z values. Some unrealistically high and low Z values might be found in the raster height models.

Completeness_Report:

Some of the 2012 lidar covers a sizeable portion of block 307B adjacent to the L1G and L2F burn blocks, and block 608A was flown in 2011, but lidar data contemporaneous with the 2008 burns are not available. Otherwise, data are complete.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

For the 2008 lidar data, the horizontal accuracy was 0.05 meters for a flying altitude of 600 meters. In both 2011 and 2012, the horizontal accuracy was < 0.5 meters (not tested).

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report:

For 2008, the vendor reported vertical accuracies ranging from 0.05-0.1 meters. For 703C and 608A in 2011, the root mean squared differences between lidar return heights and ground surveyed heights were 0.600 and 0.642 meters, respectively. For 2012, the root mean squared difference between lidar return heights and ground surveyed heights was 0.082 meters.

Lineage:

Methodology:

Methodology_Type: Field

Methodology_Description:

Lidar data were collected in Georgia on March 5, 2008 by the National Center for Airborne Laser Mapping aboard a fixed-wing aircraft flying at 600 meters above ground level. Lidar data were collected in Eglin Air Force Base on February 5-6, 2011 and November 3, 2012 by Kucera International using a Leica ALS60 sensor aboard a fixed-wing aircraft flying at 1200 meters above ground level using a sidelap of 50%. Sensor field of view in 2011 and 2012 was 24 and 20 degrees, respectively. Sensor pulse rate in 2011 and 2012 was 176.1 and 178.6 KHz, respectively.

For more details on the 2008, 2011, and 2012 lidar surveys see the vendor reports included in the full data package download (\Supplements\*.pdf).

Process_Step:

Process_Description:

Kucera International delivered classified point cloud information in the form of LAS files. Ground-classified returns were binned into one-meter grids and summarized to produce Digital Terrain Models (DTMs). Underlying DTM heights were then subtracted from remaining nonground-classified returns to calculate height-above-ground of nonground-classified returns. Canopy Height Models (CHM) and Canopy Surface Models (CSM) were created by binning and summarizing nonground returns into one-meter grids, with Z values representing canopy heights or orthometric heights, respectively. Mean Intensity Surfaces were created by binning and averaging lidar return intensity values into one-meter grids.

See the 2008, 2011, and 2012 lidar vendor reports included in the full data package download (\Supplements\*.pdf) for further details.

Process_Date: 2013

Process_Step:

Process_Description:

Percent canopy cover is defined as the percentage of first lidar returns greater than 1.37 meters above ground. Percent canopy cover grids were generated using the following lastools (https://www.cs.unc.edu/~isenburg/lastools/) commands:

lasground -i *.las -all_returns -replace_z

lascanopy -i *.las -merged -step 2.5 -height_cutoff 1.37 -cov

Percent canopy cover grids output from lastools were then projected into UTM coordinates using R.

Process_Date: 2014

Process_Step:

Process_Description:

After original publication of these data, it was discovered that the DTM and CSM for Eglin 703C were hillshades and had been normalized to height above ground. To correct this and maintain consistency, all of the rasters files were reproduced. Mean intensity grids (INT), canopy surface models (CSM), canopy height models (CHM), and digital terrain models (DTM) were created using LAStools (https://www.cs.unc.edu/~isenburg/lastools/) and projected into UTM Zone 16 NAD and mosaicked (in the case of the 2012 products) using ArcGIS. The vendor-provided classification of ground points was used to define the ground surface. The 1-meter DTMs were created using the blast2dem utility of LAStools, which created a triangulated irregular network (TIN) with ground-classified returns that was then rasterized. Each 1-meter cell within the CSM and CHM took the value of the maximum height within that cell. Returns above 40 meters plus the maximum digital terrain model value, which differed for each area, were excluded from CSMs, and returns above 40 meters height-above-ground level were excluded from CHMs. Specific LAStool commands for each product are below:

INT:
lascanopy -i *.laz -merged -int_avg -step 1

CSM:
lascanopy -i *.laz -merged -max -step 1 -drop_z_above [40 + maximum value of DTM]

CHM:
lasheight -i *.laz -replace_z
lascanopy -i *.las -merged -max -step 1 -drop_z_above 40

DTM:
blast2dem -i *.laz -merged -keep_class 2 -step 1

Isenburg, M. 2015. LAStools - efficient tools for LiDAR processing, version 150304, https://www.cs.unc.edu/~isenburg/lastools/ (original URL: lastools.org).

Process_Date: 2016

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Pixel

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Overview:

This data package contains raw lidar, raster, and percent canopy data as specified below.

Let:
YYYY = year (2008, 2011, or 2012); and
LOCATION = CNT, SE, NE, NW, Eglin 608a, Eglin 703c, or Eglin.

RAW LIDAR DATA FILES:
\Data\YYYY_raw_lidar_LOCATION
LAZ files containing raw lidar data for the specified location and year. LAZ files are compressed LAS files.

AIRBORNE LIDAR 1 METER RASTER DATA FILES:
\Data\YYYY_rasters_LOCATION
IMG raster files (1 meter) containing data derived from the raw airborne lidar files collected for the specified location and year. There are four different derived rasters: Canopy Height Model (chm), Canopy Surface Model (csm), Digital Terrain Model (dtm), or Mean Intensity Surfaces (int).

PERCENT COVER DATA FILES:
\Data\YYYY_percent_cover_LOCATION
TIF raster files containing percent canopy cover data derived from the raw lidar files.

SUPPLEMENTAL FILES:
This package also contains 7 supplemental files which include vendor reports for the 2008, 2011, and 2012 surveys in addition to a short summary of the RxCADRE project.

\Supplements\2008_LIDAR_Survey_Ichauway.pdf: Adobe Acrobat PDF/a file containing specific details of the 2008 lidar survey of Ichauway Forest.

\Supplements\2011_59802_Eglin_AFB_LiDAR_MetaData_Simple.pdf: Adobe Acrobat PDF/a file containing specific details of the 2011 lidar survey of Eglin 608A and 703C.

\Supplements\2011_59802_Summary_Report.pdf: Adobe Acrobat PDF/a file containing a summary report of the 2011 lidar survey of Eglin 608A and 703C.

\Supplements\2012_60106_LIDAR_ProjectSummary_DeliveryList.pdf: Adobe Acrobat PDF/a file containing the project summary and deliver list for the 2012 lidar survey of Eglin AFB.

\Supplements\2012_LeicaALS60_SensorParameters_LargeUnit.pdf: Adobe Acrobat PDF/a file containing information on the Leica ALS60 sensor parameters (large units) for the 2012 lidar survey of Eglin AFB.

\Supplements\2012_LeicaALS60_SensorParameters_SmallUnits.pdf: Adobe Acrobat PDF/a file containing information on the Leica ALS60 sensor parameters (small units) for the 2012 lidar survey of Eglin AFB.

\Supplements\RxCADRE_Project_Overview.pdf: Adobe Acrobat PDF/a file containing an overview of the entire RxCADRE project.

Entity_and_Attribute_Detail_Citation:

None provided

Metadata_Reference_Information:

Metadata_Date: 20220622

Metadata_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Andrew T. Hudak

Contact_Organization: Rocky Mountain Research Station

Contact_Position: Research Forester

Contact_Address:

Address_Type: mailing and physical

Address: 1221 South Main St

City: Moscow

State_or_Province: ID

Postal_Code: 83843

Country: USA

Contact_Voice_Telephone: 208-882-3557

Contact_Electronic_Mail_Address: andrew.hudak@usda.gov

Metadata_Standard_Name: FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001.1-1999