2011-2013 Indiana Statewide Imagery and LiDAR Program: Lake Michigan Watershed Counties

Create custom data files by choosing data area, product type, map projection, file format, datum, etc.

Simple download of data files. Orthometric heights version.

A .kmz footprint of the dataset's extent available for download.

Date that the source FGDC record was last modified.

Converted from FGDC Content Standards for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

The LiDAR data collected for this task order. | Source Geospatial Form: vector digital data | Type of Source Media: disc

Block 7(partial) and 8 - Using an Optech Gemini LiDAR system, 152 flight lines of high density data, at a nominal pulse spacing (NPS) of 1.5 meter (1.0 meters for Floyd and Dearborn Counties)and Blocks 5, 6, and 7(partial) - Using Leica ALS LiDAR systems, 219 flight lines of high density data were collected, at a nominal pulse spacing (NPS) of 1.5 meter. Multiple returns were recorded for each laser pulse along with an intensity value for each return. A total of thirty (30) missions were flown January 31, 2012 December 13, 2012. Eleven (11) airborne global positioning system (GPS) base stations were used in support of the LiDAR data acquisition. 248 ground control points were surveyed through static methods. The geoid used to reduce satellite derived elevations to orthometric heights was Geoid09. The horizontal datum used for this survey is North American Datum 1983 (NSRS2007), Indiana State Plane Coordinate System, East Zone, and expressed in US Survey Feet. The vertical datum used for this survey is North American Vertical Datum 1988 (NAVD88), and expressed in US Survey Feet. Airborne GPS data was differentially processed and integrated with the post processed IMU data to derive a smoothed best estimate of trajectory (SBET). The SBET was used to reduce the LiDAR slant range measurements to a raw reflective surface for each flight line. System Parameters: - Type of Scanner = Optech Gemini - Data Acquisition Height = 7,380-feet AGL - Scanner Field of View = 20 degrees - Scan Frequency = 32 Hertz - Pulse Repetition Rate - 100.0 Kilohertz - Aircraft Speed = 150 Knots - Swath Width = 5374 feet - Number of Returns Per Pulse = Maximum of 4 - Distance Between Flight Lines = Varies. System Parameters: - Type of Scanner = Leica ALS50-II / ALS60 / ALS70 - Data Acquisition Height = 7800 feet AGL - Scanner Field of View = 40 degrees - Scan Frequency = Varies - Pulse Repetition Rate - 99 Kilohertz - Aircraft Speed = Varies - Swath Width = 5678 feet - Number of Returns Per Pulse = Maximum of 4 - Distance Between Flight Lines = Varies.

The Optech Gemini and Leica systems' LiDAR system calibration and performance is verified on a periodic basis using Woolpert's calibration range. The calibration range consists of a large building and runway.

The edges of the building and control points along the runway have been located using conventional survey methods. Inertial measurement unit (IMU) misalignment angles and horizontal accuracy are calculated by comparing the position of the building edges between opposing flight lines. The scanner scale factor and vertical accuracy is calculated through comparison of LiDAR data against control points along the runway. Field calibration is performed on all flight lines to refine the IMU misalignment angles. IMU misalignment angles are calculated from the relative displacement of features within the overlap region of adjacent (and opposing) flight lines. The raw LiDAR data is reduced using the refined misalignment angles.

Once the data acquisition and GPS processing phases are complete, the LiDAR data was processed immediately to verify the coverage had no voids. The GPS and IMU data was post processed using differential and Kalman filter algorithms to derive a best estimate of trajectory. The quality of the solution was verified to be consistent with the accuracy requirements of the project.

The individual flight lines were inspected to ensure the systematic and residual errors have been identified and removed. Then, the flight lines were compared to adjacent flight lines for any mismatches to obtain a homogeneous coverage throughout the project area. The point cloud underwent a classification process to determine bare-earth points and non-ground points utilizing "first and only" as well as "last of many" LiDAR returns. This process determined bare-earth points (Class 2), noise (Class 7), water (Class 9) ignored ground (Class 10), unclassified data (Class 1), overlap points (Class 12), and bridges (Class 13). The bare-earth (Class 2 - Ground) LiDAR points underwent a manual QA/QC step to verify that artifacts have been removed from the bare-earth surface. The surveyed ground control points are used to perform the accuracy checks and statistical analysis of the LiDAR dataset.

Breaklines defining lakes, greater than two acres, and double-line streams, wider than 100 feet (30.5 meters), were compiled using digital photogrammetric techniques as part of the hydrographic flattening process and provided as ESRI Polyline Z and Polygon Z shape files. Breaklines defining water bodies and streams were compiled for this task order. The breaklines were used to perform the hydrologic flattening of water bodies, and gradient hydrologic flattening of double line streams. Lakes, reservoirs and ponds, at a nominal minimum size of two (2) acres or greater, were compiled as closed polygons. The closed water bodies were collected at a constant elevation. Rivers and streams, at a nominal minimum width of 100 feet (30.5 meters), were compiled in the direction of flow with both sides of the stream maintaining an equal gradient elevation. The hydrologic flattening of the LiDAR data was performed for inclusion in the National Elevation Dataset (NED).

The NOAA Office for Coastal Management (OCM) received the files in laz format. The files contained Lidar elevation and intensity measurements.

The Indiana East State Plane counties of Elkhart, St. Joseph and LaGrange were received in Indiana State Plane projection east (1301) in feet and NAVD88 Geoid 09 vertical datum. The Indiana West State Plane counties of LaPorte, Porter and Lake were said to be in Indiana State Plane west (1302) akin to the eastern counties however at closer inspection these tiles did not align with the eastern counties after transformation to geographic coordinates and ellipsoidal heights. It was then discovered that the tiles were in fact already in geographic WGS84. Therefore a transformation of horizontal coordinates was completed on the eastern counties and all counties received an ellipsoidal transformation. The resulting tiles align to each other and to existing OCM Lake Michigan bathymetry/topographical collections and Ohio topographical data.

OCM performed the following processing to the data to make it available within the Digital Coast:

1. The eastern Indiana county data were converted from State Plane coordinates to geographic coordinates.

2. The data were converted from NAVD88 (orthometric) heights to GRS80 (ellipsoid) heights using Geoid 09.

3. The high and low error outlier elevations were removed and variable length records (vlr) were removed.

4. Originally classed points as bridges (classification 13) were moved to class 15 to avoid conflict in the Data Access Viewer system.

Class 15 was returned to the original class 13 (bridges). A few scattered points were found in classes that were not specified/defined. These were reclassed into class 1.