2008 City of Baltimore Lidar
This kmz file shows the extent of coverage for the 2008 City of Baltimore lidar data
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.
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
KCI/Sanborn Joint Venture Partnership, L.L.C. (hereafter referred to as KCI/Sanborn)
Lidar Dataset Supplemental Information
- KCI/Sanborn Joint Venture Partnership, L.L.C. (hereafter referred to as KCI/Sanborn)
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| As needed
||This LIDAR operation was designed to provide a high density set of masspoints within
the defined areas. The data sets are suitable for the development of contours for
use in hydraulic/hydrologic model development, and for assessing environmental impacts.
Typical uses for the dataset include FEMA Flood Map Modernization, DFIRM map updates,
watershed delineation and other hydro studies per FEMA specifications, as well as
general use by the City of Baltimore.
|| Unknown to Unknown
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Surface Model
- Digital Elevation Model
- Hydrologic Modeling
- Drainage Area
- Coastal Elevation
- Terrain Elevation
- City of Baltimore
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
- Sanborn Map Company, Inc.
| Processing Steps
- Using a Leica Geosystems ALS50 Light Detection And Ranging (LiDAR) system, 29 flight
lines of an average density of 1.0 meter ground sample distance, data were collected
over areas in Baltimore City, MD (approximately 90 square miles). Multiple returns
were recorded for each laser pulse along with an intensity value for each return.
The data acquisition occurred in 1 mission on April 15, 2008. During the LIDAR campaign,
the Sanborn field crew conducted a GPS field survey to establish final coordinates
of the ground base stations for final processing of the base-remote GPS solutions.
Airborne GPS data was differentially processed and integrated with the post processed
IMU data to derive a Smoothed Best Estimate of Trajectory (SBET). The SBET was used
to reduce the LiDAR slant range measurements to a raw reflective surface for each
flight line. The overlap between flight lines was removed to provide a homogeneous
coverage, and the coverage was classified to extract a bare earth digital elevation
model (DEM). Airborne GPS is differentially processed using the GrafNAV V7.50 software
by Waypoint Consulting of Calgary, Alberta, Canada. The PDOP and distance separation
is as follows: The classification and quality control (QC) of LiDAR data is carried
out using TerraScan software by Terrasolid Limited of Helinski, Finland. IMU data
provides information concerning roll, pitch and yaw of collection platform during
collection event. IMU information allows the pulse vector to be properly placed in
3D space allowing the distance from the aircraft reference point to be properly positioned
on the elevation model surface. The IMU data is processed using the PosPac V4.2 software
by Applanix Corporation of Richmond Hill, Ontario, Canada. The reflective surface
is derived using the ALS Post Processor software by Leica Geosystems GIS & Mapping
Division of Atlanta, Georgia.
- The NOAA Coastal Services Center (CSC) received data in LAS v1.1 format. The files
contained LiDAR elevation and intensity measurements. The data were received in state
plane coordinates (Maryland; NAD83) and vertically referenced to NAVD88 using the
Geoid03 model. The vertical units of data were feet. The data were classified according
to ASPRS LAS classification scheme (0 = never classified, 1 = unclassified, 2 = ground
3 = low vegetation, 7 = noise, 12 = overlap). CSC performed the following processing
for data storage and Digital Coast provisioning purposes: 1. The data were converted
from state plane coordinates to geographic coordinates (NAD83). 2. The data were converted
from orthometric heights to ellipsoidal heights (GRS80) using Geoid 03. 3. The vertical
units of the data were changed from feet to meters. 2. The LAS data were sorted by
latitude and the headers were updated. 3. The data were converted to LAZ format.
- The NOAA National Geophysical Data Center (NGDC) received lidar data files via ftp
transfer from the NOAA Coastal Services Center. The data are currently
being served via NOAA CSC Digital Coast at http://www.csc.noaa.gov/digitalcoast/.
The data can be used to re-populate the system. The data are archived in LAS or LAZ
The LAS format is an industry standard for LiDAR data developed by the American Society
of Photogrammetry and Remote Sensing (ASPRS); LAZ is a loseless compressed version
LAS developed by Martin Isenburg (http://www.laszip.org/). The data are exclusively
in geographic coordinates (either NAD83 or ITRF94). The data are referenced vertically
the ellipsoid (either GRS80 or ITRF94), allowing for the ability to apply the most
up to date geoid model when transforming to orthometric heights.
Metadata Last Modified: 2013-01-22
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