2021 Miami-Dade ITD Lidar DEM: Miami-Dade County, FL

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Bulk download of data files in GeoTIFF format, FL State Plane East NAD83(2011) US feet coordinates and elevations in NAVD88 (GEOID18) feet. Note that the vertical datum (hence elevations) of the files here are different than described in this document. They will be in an orthometric datum.

Link to the breaklines, overpasses, bridges, QAQC points, and ground control points.

Link to the lidar report.

This graphic displays the footprint for this lidar data set.

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

The project was divided in two phases: Collection and classification of LiDAR data; and creation of 5-foot and 2-foot cell spaced hydro flattened mosaic DEM of the project area. The LiDAR data was collected utilizing a Riegl VQ-1560ii in a Cessna 206 from an approximate altitude of 4,200 feet above ground level, at an approximate ground speed of 110 knots at a pulse rate repetition of 3,592 kHg, resulting in an average of 28 points per square meter single swath. Three areas needed reflight's due to clouds and building shadows the flight height was lowered to get under the cloud celling in these areas. These areas were collected at 2,500 feet agl at 120 knots at a pulse rate repetition of 4,000kHg. These lines were collected at 50.6 points per square meter single swath. The sensor used a 60-degree field of view. The project was flown to have 30 percent overlap between swaths for original flight plan and 60% for the 2,500 foot altitude. The Global Positioning System (GPS) data were processed using Applanix POSPac Mapping Suite version 8.4 using Smart Base method and single base methods. A fixed bias carrier phase solution was computed in forward and reverse directions. The LiDAR collection took place when Positional Dilution of Precision (PDOP) was at or below 3. Occasionally, the PDOP rose slightly above 3. This had no effect on the data. The GPS trajectory was combined with the IMU data using the Applanix POSPac software. The resulting Smoothed Best Estimate of Trajectory (SBET) was exported and used in Riegl RiProcess software to compute the laser mass point positions in Northing, Easting, and Elevations coordinates. The raw laser data were merged with the SBET using Riegl RiProcess software. The data set was processed using RiProcess, RiAnalyze, and RiWorld software where each flight line was processed to a point cloud. The data was adjusted flight line to flight line using Riegl's Scan Data Adjustment tool to ensure a proper relative calibration match between flight lines. Each flight was checked for project coverage, data gaps between overlapping flight lines, point density and then exported in LAS 1.4 format. The entire project was collected without gaps. The LAS files were projected to the NAD_1983_2011_StatePlane_Florida_East_FIPS_0901_Feet and North American Vertical Datum of 1988 (NAVD88). Ellipsoidal heights were converted to orthometric heights using the current Geoid 18. The LAS files were imported to TerraSolid, LTD TerraScan software to be classified to bare earth ground and later feature coded to USGS specifications. The LAS files contain 12 classifications: 1 = unclassified; 2 = ground (or Bare Earth); 3 = low vegetation 0 - 5 ft; 4 = med veg 5 - 25 ft; 5 = high veg 25 - above; 6 = building; 7 = low point (noise); 9 = water; 17 = bridges; 18 = high noise; 20 = ignored ground. The LiDAR data was run through an automated ground and building classification using TerraScan software. A manual check of the building classification was done. The vegetation heights were assigned by an automated process after the bare-earth and buildings were classified. Breaklines were digitized from the LiDAR data in ArcMap

Breaklines were digitized from the LiDAR data in ArcMap and elevations were assigned using LP360 and ArcGIS. The double line linear hydrographic features were hydro-enforced with downhill constraints to model correct flow patterns. Water bodies were hydro-flattened to ensure uniform elevation across the feature. DEMs were created using TerraScan Project. The bare-earth LAS data was loaded into the software along with the tile layout and hydro shapefile collected from the LAS data set. DEMS were produced at a 5ft and 2ft cell size and hydro-flattened. To QC the DEMs Global Mapper was used to check for completeness of the tiles and that the hydro features were flattened and represented correct elevations. Once the QC was complete the files were exported out of ArcGIS to create Arc DEM, and TerraScan project for Geotiffs.

The NOAA Office for Coastal Management (OCM) received 10,904 GeoTIFF files from the Miami-Dade County Information Technology Department (ITD). The files were in Florida State Plane East NAD83(2011), US feet coordinates and the elevations were in NAVD88 (GEOID18) feet. The bare earth raster files were at a 2 feet grid spacing. OCM assigned the appropriate EPSG codes (Horiz - 6438, Vert - 6360) and copied the raster files to AWS S3 for Digital Coast storage and provisioning purposes.