2019 - 2021 La DOTD Lidar DEM: Florida Parishes, LA

Original Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the Louisiana Lidar 2017 project. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create a 0.5 meter hydro-flattened Raster DEM.

Original Dataset Geographic Extent:

LA_2021FloridaParishes_1 (Work Unit 300569) covers approximately 1272.5 square miles and includes:

Louisiana Lidar 2017 Block 26NE, covering approximately 231 square miles in St. Helena and Tangipahoa Parishes

Louisiana Lidar 2017 Block 26SE, covering approximately 369 square miles in Livingston, St. Helena, and Tangipahoa Parishes

Louisiana Lidar 2017 Block 30NE, covering approximately 258.50 square miles in Pearl River and Washington Parishes

Louisiana Lidar 2017 Block 30NW, covering approximately 414 square miles in Tangipahoa and Washington Parishes

LA_2021FloridaParishes_2 (Work Unit 300570) covers approximately 1313.14 square miles and includes:

Louisiana Lidar 2017 Block 30SE, covering approximately 290 square miles in Pearl River and St. Tammany Parishes

Louisiana Lidar 2017 Block 30SW, covering approximately 535.14 square miles in St. Tammany, Tangipahoa, and Washington Parishes

Louisiana Lidar 2017 Block 31NE, covering approximately 488 square miles in St. Tammany Parish

LA_2021FloridaParishes_3 (Work Unit 300571) covers approximately 897 square miles and includes:

Louisiana Lidar 2017 Block 25NE, covering approximately 155 square miles in Livingston and Tangipahoa Parishes

Louisiana Lidar 2017 Block 25SE, covering approximately 435 square miles in Tangipahoa and Washington Parishes

Louisiana Lidar 2017 Block 31NW, covering approximately 307 square miles in Livingston, St. John the Baptist, St. Tammany, and Tangipahoa Parishes

LA_2021FloridaParishes_4 (Work Unit 300868) covers approximately 50 square miles and includes:

Louisiana Lidar 2017 Block 31SW, covering approximately 50 square miles in St. John the Baptist and St. Charles Parishes

Original Dataset Description: Louisiana Lidar 2017 project called for the Planning, Acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.35 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal projection/datum of NAD83 (2011), Universal Transverse Mercator, meters and vertical datum of NAVD88 (GEOID12B), meters. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to individual 1,500 m x 1,500 m tiles, as tiled Intensity Imagery, and as tiled bare earth DEMs; all tiled to the same 1,500 m x 1,500 m schema. LA DOTD acquired and initially post-processed lidar data for the following blocks- 25SE, 25NE, 26NE, 26SE, 30NW, 30NE, 30SE, 31NE, and 31S. The Sanborn Map Company (Sanborn) acquired and initially post-processed lidar for the following blocks- 30SW and 31NW.

Original Dataset Ground Conditions: Lidar was collected while no snow was on the ground and rivers were at or below normal levels.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the GeoTIFF files hosted by USGS on Amazon Web Services.

To acquire detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments and elevation modeling, etc. Classified LAS files are used to show the manually reviewed bare earth surface. This allows the user to create Intensity Images, Breaklines and Raster DEM. The purpose of these lidar data was to produce high accuracy 3D hydro-flattened Digital Elevation Model (DEM) with a 0.5 meter cell size. These raw lidar point cloud data were used to create classified lidar LAS files, intensity images, 3D breaklines, hydro-flattened DEMs as necessary.

Raster File Type = GeoTIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 0.5 Meter

Interpolation or Resampling Technique = Triangulated Irregular Network

Required Vertical Accuracy = 19.6 cm NVA

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the Office for Coastal Management or its partners.

To the extent possible under law, the U.S. Government has waived all copyright and related or neighboring rights to this dataset.

Data is available online for bulk and custom downloads.

None

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 limitations.

Horizontal accuracy testing requires well-defined checkpoints that can be identified in the dataset. Elevation datasets, including lidar datasets, do not always contain well-defined checkpoints suitable for horizontal accuracy assessment. However, the ASPRS Positional Accuracy Standards for Digital Geospatial Data (2014) recommends at least half of the NVA vertical check points should be located at the ends of paint stripes or other point features visible on the lidar intensity image, allowing them to double as horizontal check points.

No checkpoints were photo-identifiable in the intensity imagery; horizontal accuracy could not be tested on this dataset.

This data set was produced to meet ASPRS Positional Accuracy Standard for Digital Geospatial Data (2014) for a 10-cm RMSEz Vertical Accuracy Class.

USGS Determined DEM Vertical Accuracy:

Non-Vegetated Vertical Accuracy (NVA) = 4.19 cm RMSE

Vegetated Vertical Accuracy (VVA) = 19.34 cm at 95th Percentile

Datasets contain complete coverage of tiles. No points have been removed or excluded. A visual qualitative assessment was performed to ensure data completeness. There are no void areas or missing data. The raw point cloud is of good quality and data passes Non-Vegetated Vertical Accuracy specifications.

Data covers the entire area specified for this project.

The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTIFF files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS.