2023 IN DNR Lidar DEM: Indiana Coastline

Product: These are Digital Elevation Model (DEM) data as part of the required deliverables for the lidar project. Class 2 (Ground) lidar points in conjunction with the hydro breaklines were used to create a 1 ft hydro-flattened Raster DEM.

Geographic Extent: Cook county, Illinois; Lake, LaPorte, and Porter counties, Indiana; and Berrien county, Michigan; covering approximately 136 square miles.

Dataset Description of Original Data: The lidar 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 meters. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification. The data was developed based on a horizontal projection/datum of NAD83(HARN), Indiana West Feet, and vertical datum of NAVD88 (GEOID18) Feet. Lidar data was delivered as processed Classified LAS 1.4 files, formatted to 2503 individual 1250 ft x 1250 ft tiles clipped to the DPA, as tiled Intensity Images and tiled bare-earth DEMs; all tiled to the same 1250 ft x 1250 ft schema.

Ground Conditions: Lidar was collected in March 2023, while no snow was on the ground and rivers were at or below normal levels. Sanborn Map Company, Inc. established a total of 25 accuracy check points, 20 in Bare Earth and Urban landcovers (20 NVA points), 5 in Tall Grass and Brushland/Low Trees categories (5 VVA points), that were used to assess the vertical accuracy of the data.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV).

The NOAA Office for Coastal Management (OCM) received a copy of this data. The data were processed to the NOAA Digital Coast Data Access Viewer (DAV) to make the data available for bulk and custom downloads. In addition to these bare earth Digital Elevation Model (DEM) data, the lidar point data that these DEM data were created from, are also available. These data are available for custom download at the link provided in the URL section of this metadata record.

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 1 ft cell size. These lidar point cloud data were used to create intensity images, 3D breaklines, and hydro-flattened DEMs as necessary.

Raster File Type = TIFF

Bit Depth/Pixel Type = 32-bit float

Raster Cell Size = 1 foot

Interpolation or Resampling Technique = Bilinear Interpolation

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.

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.

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

Actual NVA accuracy was found to be RMSEz = 3 cm, equating to +/- 5.88 cm at 95% confidence level. Actual VVA accuracy was found to be +/- 4 cm at the 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 DPA specified for this project.

Data is backed up to cloud storage.

Data were collected by the Sanborn Mapping Company. The data were provided to the NOAA Office for Coastal Management (OCM) and processed to make it available for custom download from the NOAA Digital Coast Data Access Viewer (DAV) and for bulk download from AWS S3.