MD/PA Sandy Supplemental Lidar Data Acquisition and Processing Production Task USGS Contract No. G10PC00057 Task Order No. G14PD00397 Woolpert Order No. 74333 CONTRACTOR: Woolpert, Inc. This task is for a high resolution data set of lidar covering approximately 1,845 square miles. The lidar data was acquired and processed under the requirements identified in this task order. Lidar data is a remotely sensed high resolution elevation data collected by an airborne platform. The lidar sensor uses a combination of laser range finding, GPS positioning, and inertial measurement technologies. The lidar systems collect data point clouds that are used to produce highly detailed Digital Elevation Models (DEMs) of the earth's terrain, man-made structures, and vegetation. The task required the LiDAR data to be collected at a nominal pulse spacing (NPS) of 0.7 meters. The final products include classified LAS, one (1) meter pixel raster DEMs of the bare-earth surface in ERDAS IMG Format, and 8-bit intensity images. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Additional deliverables include hydrologic breakline data, control data, tile index, lidar processing and survey reports in PDF format, FGDC metadata files for each data deliverable in .xml format, and LAS swath data. Ground conditions: Water at normal levels; no unusual inundation; no snow; leaf off. Coastal tiles 18SVH065720 and 8SVH095690 contain no lidar points as they exist completely in water. A DEM IMG was generated for these two tiles as the digitized hydro breakline assumed the data extent in the area. As such only 2568 LAS and Intensity files will be delivered along with 2570 DEM IMG's.This is a MD iMAP hosted service. Find more information at https://imap.maryland.gov.Image Service Link: https://mdgeodata.md.gov/lidar/rest/services/BaltimoreCity/MD_baltimorecity_hillshade_m/ImageServer

These data sets represent 23 geographic 5-minute indexes for the counties of Maryland, one 2 1/2-minute index for Washington D.C., and 1-mile square index for Baltimore City. There are 25 vector polygon data sets covered by this metadata report.

In the spring of 2008, the City of Baltimore expressed an interest to upgrade the City GIS Database with mapping quality airborne LiDAR data. The City of Baltimore currently had in place a contract for mapping GIS/services with the KCI/Sanborn Joint Venture Partnership, L.L.C. under Project 1051. The City of Baltimore issued Change Order #1 on on Project 1051 for the LiDAR acquisition and processing. KCI/Sanborn acquired the LiDAR data over the City of Baltimore (approximately 90 square miles) during one long mission on 15 April 2008. A Leica Airborne Airborne Laser Scanner Model ALS 50 was used in a Sanborn Aero Commander 500B (Registration N6172X) to acquire the data. The airborne mission was flown 15 April 2008. The LiDAR system acquired calibration data the same day by conducting flight passes over a known ground surface before and the LiDAR mission. During final data processing, the calibration parameters were used in the final post-processing software. The acquired LiDAR data were processed to obtain the following deliverables: -DEMs of first and last returns and bare earth (all point data) -LAS format data in a tile grid provided by the City/KCI -Gridded DEM in ESRI format (Arc Binary Grid -Arc/INFO Lattice ) produced from Bare Earth Mass Points in 1-meter resolution (Grid size) -Associated FGDC compliant metadata in XML format The project specifications called for the LiDAR survey to comply with industry standard FEMA guidelines for accuracy. The FEMA requirement for this type of mapping calls for vertical errors not to exceed 0.185 meter (0.61 feet) RMSE when compared with ground check points over open flat terrain and 0.370 meter (1.22 feet) for other types of terrain. This accuracy requirement was comfortably met with comparing LiDAR derived elevations against 50 ground control check points provided by KCI Technologies. These control points were photo control points used as part of the photogrammetric mapping project and independent LiDAR checkpoints surveyed by KCI and Mercado after the data was delivered. The RMSE error observed was 0.058 meter (0.189 feet) over all 50 check points.

Aerial Cartographics of America (ACA) collected 750 square miles covering Baltimore County. The nominal pulse spacing for this project was 1 point every 0.7 meters. Dewberry used proprietary procedures to classify the LAS according to project specifications: 0-Never Classified, 1-Unclassified, 2-Ground, 7-Low Noise, 9-Water, 10-Ignored Ground due to breakline proximity. Dewberry produced 3D breaklines and combined these with the final LiDAR data to produce seamless hydro-conditioned DEMs for the project area. The data was formatted according to the Baltimore County tile naming convention.This is a MD iMAP hosted service. Find more information at https://imap.maryland.gov.Image Service Link: https://mdgeodata.md.gov/lidar/rest/services/Baltimore/MD_baltimore_slope_m/ImageServer