2018 FEMA Lidar: Region 9, AZ

Product: Processed, classified lidar point cloud data tiles in LAS 1.4 format.

Geographic Extent: Approximately 10,547 square miles across 11 AOIs in California and Arizona.

Dataset Description: The CA-AZ FEMA R9 Lidar 2017 D18 lidar project called for the planning, acquisition, processing, and production of derivative products of lidar data to be collected at a nominal pulse spacing (NPS) of 0.7 meters. Project specifications were based on the U.S. Geological Survey National Geospatial Program Base Lidar Specification, Version 1.2. The data was developed based on a horizontal datum/projection of NAD83 State Plane Arizona Central Zone (FIPS Zone 0202), International Feet (EPSG Code 2223), and a vertical datum of NAVD88 (GEOID12B), International Feet. Lidar data was delivered as processed LAS 1.4 files formatted to 5,100 individual 4,500-feet x 4,500-feet tiles.

Ground Conditions: Lidar was collected on January 6, 2018, 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 and meet ASPRS vertical accuracy guidelines, Woolpert established 120 ground control points in the Arizona East AOI that were used to calibrate the lidar to known ground locations established throughout the project area. An additional 146 independent accuracy checkpoints (94 NVA points and 52 VVA points), were collected in the Arizona East AOI and used to assess the vertical accuracy of the data. These checkpoints were not used to calibrate or post process the data.

High quality elevation data products are critical for riverine floodplain study and mapping for the National Flood Insurance Program. This acquisition allows FEMA Region IX to produce floodplain analysis where it is needed, to provide updates to flood insurance rate maps, and to produce floodplain administration decision support tools.

FEMA, in administration of the National Flood Insurance Program and under FEMAs Risk Mapping Assessment and Planning (Risk MAP) program, orders these elevation products to meet or exceed the quality specifications published by the US Geological Survey for acceptance into the 3-D Elevation Program (3-DEP). Data of this quality is interpreted as sufficient for floodplain engineering studies, analysis, and mapping of flood hazard.

USGS Contract No. G16PC00022 Task Order No. 140G0218F0027. CONTRACTOR: Woolpert. Sub-Contractors: Aerial Services, Inc. (ASI), Aero-Graphics, Keystone Aerial Surveys.

The following are the USGS lidar fields in JSON:

{

"ldrinfo" : {

"ldrspec" : "USGS NGP Base Specifications v1.2",

"ldrsens" : "Leica ALS 70 (ASI)",

"ldrmaxnr" : "4",

"ldrnps" : "2.44",

"ldrdens" : "0.64",

"ldranps" : "2.44",

"ldradens" : "0.64",

"ldrfltht" : "1981",

"ldrfltsp" : "150",

"ldrscana" : "40",

"ldrscanr" : "50",

"ldrpulsr" : "272",

"ldrpulsd" : "5",

"ldrpulsw" : "2.5",

"ldrwavel" : "1064",

"ldrmpia" : "1",

"ldrbmdiv" : "0.22",

"ldrswatw" : "1442",

"ldrswato" : "30",

"ldrgeoid" : "GEOID12B"

},

"ldraccur" : {

"ldrchacc" : "0",

"rawnva" : "0",

"rawnvan" : "0",

"clsnva" : "0",

"clsnvan" : "0",

"clsvva" : "0",

"clsvvan" : "0"

},

"lasinfo" : {

"lasver" : "1.4",

"lasprf" : "6",

"laswheld" : "Geometrically unreliable points were identified using a combination of automated and manual techniques and subsequently classified as high or low noise and given the standard Withheld bit.",

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

"lasintr" : "16",

"lasclass" : {

"clascode" : "1",

"clasitem" : "Processed but not classified"

},

"lasclass" : {

"clascode" : "2",

"clasitem" : "Bare earth ground"

},

"lasclass" : {

"clascode" : "7",

"clasitem" : "Noise"

},

"lasclass" : {

"clascode" : "9",

"clasitem" : "Water"

},

"lasclass" : {

"clascode" : "10",

"clasitem" : "Ignored ground"

},

"lasclass" : {

"clascode" : "17",

"clasitem" : "Bridge Decks"

},

"lasclass" : {

"clascode" : "18",

"clasitem" : "High Noise"

}

}}

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.

Microsoft Windows 10 Version 1607 (Build 14393.2189); ArcMap 10.3; ArcCatalog 10.3; TerraScan ver. 17; TerraModeler ver. 17; Geocue 2017.2.20.0.

This project required Non-Vegetated Vertical Accuracy (NVA) to be tested on the raw lidar point cloud swath data. The dataset was required to meet a target value of 19.6 cm at a 95% confidence level using an RMSEz target value of 10 cm x 1.9600. Testing was assessed and reported using guidelines developed by the National Digital Elevation Program (NDEP) and the American Society for Photogrammetry and emote Sensing (ASPRS).

The raw NVA was to be calculated with independent checkpoints that were not used in the calibration or post processing of the lidar point cloud data. Checkpoints were to be distributed throughout the project

area and located in bare earth and urban (non-vegetated) land cover classes. Testing was performed using TINs created from the final calibrated and controlled swath data. For each NVA checkpoint, an elevation value was derived from the TIN at the point’s x,y location. This value was compared to the checkpoint’s surveyed elevation value.

For the California AOIs, the raw NVA was tested using 145 checkpoints. These checkpoints were surveyed using GPS techniques. See the survey report for acquisition methodologies. This dataset was tested to be

0.049 meters using an RMSEz of 0.096 meters x 1.9600.

For the Arizona AOIs, the raw NVA was tested using 94 checkpoints. These checkpoints were surveyed using GPS techniques. See the survey report for acquisition methodologies. This dataset was tested to be

0.119 meters using an RMSEz of 0.061 meters x 1.9600.

These 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.

Data covers the entire area specified for this project.

Data is backed up to tape and to cloud storage.