2015 NRCS Lidar: Saginaw County, MI

Geographic Extent: Saginaw County, MI, covering approximately 815 square miles.

Dataset Description: This data was part of a joint project between USDA Natural Resources Conservation Service (NRCS), USGS, and the state of Michigan to collect 31 counties of Michigan in 2016. Though the overall project has 2016 in the name, this Saginaw County data was collected in 2015. The Saginaw collection called for the planning, acquisition, processing and derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.7 meter. Project specifications are based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.0. The data was developed based on a horizontal projection/datum of Michigan State Plane South, NAD83, international feet and vertical datum of NAVD1988 (GEOID12A), international feet. Lidar data was delivered in RAW flight line swath format, then processed to create Classified LAS 1.2 Files formatted to 991 individual 5000 foot X 5000 foot tiles. Corresponding Intensity Images and Bare Earth DEMs tiles were created with the same 5000 foot X 5000 foot tile schema. Breaklines were produced in Esri geodatabase format. Processing by NOAA for ingest into the Digital Coast Data Access Viewer changed the projection and datum to NAD83(2011) ellipsoid heights in meters with geographic coordinates in the cloud optimized point cloud version of LAZ.

Ground Conditions: Lidar was collected in spring of 2015, while no snow was on the ground and rivers were at or below normal levels. In order to post process the Lidar data to meet task order specifications, Spicer Group Inc established a total of 120 Land Cover control points (52 QC checkpoints, 68 calibration control points) which were used to calibrate the Lidar to known ground locations established throughout the Saginaw County, MI project area. 28 additional check points were surveyed by Kucera for the accuracy check of the initial acquisition. these 28 points have been added to the NVA Lidar and DEM accuracy reports.

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 2 foot cell size.

These raw lidar point cloud data was used to create classified lidar LAS files, intensity images, 3D breaklines and hydro-flattened DEMs as necessary.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS-NGP Base Specification v1.0",

"ldrsens" : "Leica ALS 70 Serial Number 7121",

"ldrmaxnr" : "4",

"ldrnps" : "0.65",

"ldrdens" : "2.19",

"ldranps" : "0.65",

"ldradens" : "2.19",

"ldrfltht" : "2300",

"ldrfltsp" : "145",

"ldrscana" : "20",

"ldrscanr" : "37.7",

"ldrpulsr" : "261",

"ldrpulsd" : "4",

"ldrpulsw" : "0.48",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.22",

"ldrswatw" : "1535.70",

"ldrswato" : "9.97",

"ldrgeoid" : "National Geodetic Survey (NGS) Geoid12A"

},

"ldraccur" : {

"ldrchacc" : "0.196",

"rawnva" : "0.1842",

"rawnvan" : "68",

"clsnva" : "0.1082",

"clsnvan" : "68",

"clsvva" : "0.1201",

"clsvvan" : "44"

},

"lasinfo" : {

"lasver" : "1.2",

"lasprf" : "1",

"laswheld" : "Withheld (ignore) points were identified in these files using the standard LAS Withheld bit",

"lasolap" : "Swath "overage" points were identified in these files using the standard LAS overlap bit",

"lasintr" : "11-bit",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Undetermined/Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare earth"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "All noise"

},

"lasclass" : {

"clascode" : "6",

"clasitem" : "Bridge deck"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Overlap default"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "Overlap ground"

},

"lasclass" : {

"clascode" : "22",

"clasitem" : "Overlap bridge deck"

},

"lasclass" : {

"clascode" : "23",

"clasitem" : "Overlap noise"

},

"lasclass" : {

"clascode" : "25",

"clasitem" : "Overlap water"

},

"lasclass" : {

"clascode" : "26",

"clasitem" : "Overlap ignored ground"

}

}}

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 or 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.

MicroStation Version 8; TerraScan Version 16; TerraModeler Version 16; ESRI ArcGIS 10.3; Windows 7 Operating System; Global Mapper V17.1

\\Proj2015\122278SG2015 - Saginaw County lidar 1.66 TB

The NVA was tested using 68 independent surveys located in open terrain. The survey check points were distributed throughout the project area. The 68 independent check points (40 Spicer Group & 28 Kuchera) were surveyed using the closed level loop technique. Elevations from the classified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. The NVA RMSE was computed to be 0.181 international feet (5.52 cm). AccuracyZ has been tested to meet 19.6 cm Nonvegetated Vertical Accuracy at 95 percent confidence level using (RMSEz * 1.9600) as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. The NVA RMSE @ 95% confidence level was computed to be 0.355 international feet (10.82 cm).

The VVA was tested using 44 independent surveys located in vegetated areas. The survey check points were distributed throughout the project area. The 44 independent check points were surveyed using the closed level loop technique. Elevations from the classified lidar surface were measured for the x,y location of each check point. Elevations interpolated from the lidar surface were then compared to the elevation values of the surveyed control. The VVA RMSE was computed to be 0.241 international feet (7.35 cm). AccuracyZ has been tested to meet 29.4 cm Vegetated Vertical Accuracy at the 95th percentile as defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASPRS Guidelines. The VVA RMSE @ the 95th percentile was computed to be 0.394 international feet (12.01 cm).

These raw LAS data files include all data points collected.

No points have been removed or excluded.

A visual qualitative assessment was performed to ensure data completeness.

No void areas or missing data exist. The raw point cloud is of good quality and data passes Nonvegetated Vertical Accuracy specifications.

Data cover the entire area specified for this project.

Data is backed up to cloud storage.