2006 Federal Emergency Management Agency (FEMA) Topographic LiDAR: Cumberland and
York Counties, Maine
This kmz file shows the extent of coverage for the 2006 FEMA Cumberland and York Counties,
ME lidar data set.
In the fall of 2006, Sanborn Map Company was contracted by Camp Dresser McKee, Inc
(CDM) to execute a LiDAR (Light Detection and Ranging) survey campaign in the state
of Maine. LiDAR data in the form of 3-dimensional positions of a dense set of masspoints
was collected for the 584 sqaure miles of Cumberland and York Counties. This data
was used in the development of the bare-earth-classified elevation point data sets.
The Leica ALS-50 LiDAR system was used to collect data for the whole survey campaign.
The LiDAR system is calibrated by conducting flight passes over a known ground surface
before and after each LiDAR mission. During final data processing, the calibration
parameters are inserted into post-processing software. Six airborne GPS (Global Positioning
System) base stations were used in this project. A new point was set at the Portland
Airport (501) The other base stations were set up at National Geodetic Survey (NGS)
markers. NGS Monuments 901- PID: OC0229 and 801 - PID: OC0230 are located at the Biddeford
Airport. The other existing NGS monuments used in the network are point 701 - PID:
AJ2697, located on Bailey Island, point 702 - PID: OC0429, located at Fort Constitution,
and point 703 - PID: OC0478 located southeast of York Beach were tied to the other
three points to create a GPS survey network. The coordinates of these stations were
checked against each other with the three dimensional GPS baseline created at the
airborne support set up and determined to be within project specifications. Leica
ALS-50 LiDAR Scanner Parameters: Pulse Rate: 50,000 hertz Scan Frequency: 36 hertz
Scan Width (Half Angle): 18 degrees Flying Height: 1,200 meters above ground level
Flying Speed: ~120 knots
Cite this dataset when used as a source.
|Search and Download
|| Distributor information not available
| Point of Contact
||Federal Emergency Management Agency, Region I
Documentation links not available.
- DHS/FEMA > Federal Emergency Management Agency, U.S. Department of Homeland Security
|Data Presentation Form:
|| Digital image
|Dataset Progress Status
|Data Update Frequency:
|| As needed
||The LIDAR derived data sets, including Bare Earth and a Gridded DEM support Camp Dresser
and McKee's continued development of updated Digital Flood Insurance Rate Maps and
flood insurance studies for coastal areas located in Cumberland and York Counties,
Maine. Acquisition is Tide restricted to +/- 3 hours from Low tide.(Source: FEMA Guidelines
and Specs, Appendix N).
||2006-10-07 to 2006-10-27
|Spatial Reference System:
|Spatial Bounding Box Coordinates:
|Spatial Coverage Map:
- Digital Terrain Model
- Digital Surface Model
- Remote Sensing
- Cumberland County
- York County
| Use Constraints
|| No constraint information available
|| Fee information not available.
|| Lineage statement not available.
| Processing Steps
- Using the Leica ALS-50 Light Detection and Ranging (LiDAR) system, flight lines were
planned for standard density 1.4 meter GSD. The Flight plan for the project includes
the following specifications to fully meet the project requirements - single pass
density of approximately 1.4 square meters per sample * Swath width ~688 meters *
Flight altitude 1200 meters * flight line spacing ~516 meters with ~125 meters overlap
*Scan Frequency- 36 Hz *Scan Angle- 16 degrees * Aircraft ground speed -- 120 knots
* System Calibration pre and post mission * Two GPS base stations within 30 KM. Multiple
returns were recorded for each laser pulse along with an intensity value for each
return. The data are calibrated for geographic referencing. Points are further processed,
using TerraSolid software, to classify return values. The first and last return data
is filtered to remove the vegetation and above ground manmade features to yield a
- The NOAA Coastal Services Center (CSC) received topographic files in LAS format. The
files contained lidar elevation and intensity measurements. The data were received
in UTM Zone 19N (NAD83) coordinates and were vertically referenced to NAVD88 using
the Geoid03 model. The vertical units of the data were meters. CSC performed the following
processing for data storage and Digital Coast provisioning purposes: 1. The topographic
las files were converted from orthometric (NAVD88) heights to ellipsoidal heights
using Geoid03. 2. The topographic las files were converted from a Projected Coordinate
System (UTm 19N) to a Geographic Coordinate system (GCS). 3. The topographic las files'
horizontal units were converted from meters to decimal degrees. 4. 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: 2013-05-17
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