2015 FEMA Lidar: Michigan - Part 2

The State of Michigan (DTMB) contracted with Sanborn to provide LiDAR mapping services for 6 counties in the State of Michigan. These counties include Cass, Genesee, Kalamazoo, Lapeer, Shiawassee, and St, Joseph. This metadata record describes the three counties of Cass, Kalamazoo, and St. Joseph and the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the Entwine Point Tiles (EPT) hosted by USGS on Amazon Web Services.

Utilizing multi-return systems, Light Detection and Ranging (LiDAR) data in the form of 3-dimensional positions of a dense set of mass points was collected for the 6 counties in November and December of 2015. All systems consist of geodetic GPS positioning, orientation derived from high-end inertial sensors and highly-accurate lasers. The sensor is mounted inside an aircraft and emits rapid pulses of light, through an opening in the fuselage, that are used to determine distances between the plane and terrain below.

LAS data products are suitable for 1 foot contour generation. USGS LiDAR Base Specification 1.2, QL2. 19.6 cm NVA.

Cass County: data covers approximately 533 square miles

Kalamazoo County: data covers approximately 608 square miles

St. Joseph County: data covers approximately 552 square miles

The purpose of this data set is the acquisition and production of high resolution elevation data for the State of Michigan. This LiDAR operation was designed to create high resolution data sets that will establish an authoritative source for elevation information for the State of Michigan to create detailed surface elevation data for use in conservation planning, design, research, floodplain mapping, dam safety assessments, and hydrologic modeling.

Project Projection, Datums and Units. Projection - State Plane Michigan South. Horizontal datum - North American Datum of 1983 (NAD83 (2011)). Vertical datum - North American Vertical Datum of 1988 (NAVD88) using the latest geoid (Geoid12a) for converting ellipsoidal heights to orthometric heights. Units - intl feet

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS Lidar Base Specification 1.2, FEMA "Guidelines and Specifications for Flood Hazrad Mapping Partners".",

"ldrsens" : "Leica ALS70",

"ldrmaxnr" : "4",

"ldrnps" : "0.65",

"ldrdens" : "1.67",

"ldradens" : "2.2",

"ldranps" : "0.71",

"ldrfltht" : "2250",

"ldrfltsp" : "135",

"ldrscana" : "32",

"ldrscanr" : "64",

"ldrpulsr" : "167",

"ldrpulsd" : "10",

"ldrpulsw" : "3",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.3",

"ldrswatw" : "1222",

"ldrswato" : "30",

"ldrcrs" : "NAD_1983_2011_State_Plane_Michigan_South_2113_Ft_Intl",

"ldrgeoid" : "NGS Geoid12a"

},

"ldraccur" : {

"ldrchacc" : "19.6",

"rawnva" : "0.153",

"rawnvan" : "75",

"clsnva" : "0.130",

"clsnvan" : "76",

"clsvva" : "0.234",

"clsvvan" : "59"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Withheld (ignore) points were identified in these files using class 10.",

"lasolap" : "Swath "overage" points were identified in these files by classifying to class 11.",

"lasintr" : "10",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Unclassified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare-earth"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "All noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored Ground (Breakline Proximity)"

},

"lasclass" : {

"clascode" : "11",

"clasitem" : "Withheld (overlap)"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridges"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "Noise (high, manually identified, if needed)"

}

}}

QL2 meeting USGS 1.2 specifications

The State of Michigan Geographic Information Systems digital data have been tested and their documentation carefully reviewed. However, the State of Michigan and its representatives make no warranty or representation, either expressed or implied, with respect to the digital data and their documentation, their quality, performance, merchantability, or fitness for a particular purpose. The digital data are distributed on "as is" basis, and the user assumes all risk to their quality, the results obtained from their use, and the performance of the data. In no event will the State of Michigan or its representatives be liable for any direct, indirect, special, incidental or consequential damages resulting from and defect in the State of Michigan or in their documentation. This disclaimer of warranty is exclusive and in lieu of all others, oral or written, express or implied. No agent or employee is authorized to make any modification, extension, or addition to this warranty.

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.

Microsoft Windows 7; ESRI ArcCatalog 9.3.1.1850

The LiDAR data was evaluated using a collection of GPS surveyed checkpoints which were provided by Sanborn and a subcontractor. These checkpoints were evaluated against the LiDAR for each county resulting in a lower RMSE and standard deviation than the project required.

The control layout for the Michigan LiDAR Fall 2015 project was designed in 2 areas consisting of 3 counties each. The northern area includes Genesee, Lapeer, and Shiawassee Counties. The southern area includes Cass, Kalamazoo, and St. Joseph Counties.

The Three County Area (Cass, St. Joseph, and Kalamazoo): The LiDAR surface was evaluated using a collection of 75 GPS surveyed checkpoints for the NVA report which compared favorably to the DEM. Attribute accuracy is tested after the LiDAR processing stage. After classification of the LiDAR data, DEMs are created using the bare earth points. The DEM surface was evaluated using a collection of 76 GPS surveyed checkpoints for the NVA report which compared favorably to the DEM. The VVA report is generated from the comparison of the DEM and the 59 GPS surveyed ground control checkpoints collected within the project area in vegetated areas. Accuracy reports are not derived from the Classified LAS tiles.

The RMSE was computed to be 0.078 m, or 0.153 m @ 95th Confidence Interval defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

The VVA RMSE was computed to be 0.115 m, or 0.234 m @ 95th Percentile defined by the National Standards for Spatial Data Accuracy (NSSDA); assessed and reported using National Digital Elevation Program (NDEP)/ASRPS Guidelines.

LiDAR data is collected for the project area. Post processing of the simultaneously acquired GPS/INS is performed and applied to the laser returns to output a point cloud in the specified project coordinate system and datums. The point cloud data is then subjected to automated classification routines to assign all points in the point cloud to ground, water, overlap and unclassified point classes. Anomalous laser returns that occur infrequently are removed entirely from the data set.

LiDAR data is collected within the project area and processed. After the DEMs were created, the dataset was verified against control. Control was collected for 3 adjoining counties. Results are shown for Cass, Kalamazoo, and St. Joseph Counties.

Data is backed up to tape and to cloud storage.

The 2015 FEMA Michigan Part 2 lidar was ingested into the Data Access Viewer for custom product generation by leveraging USGS hosted Entwine Point Tiles.