2008 Federal Emergency Management Agency (FEMA) New York Lidar: Erie County

Using Leica Geosystems ALS50 Laser Systems, 89 flight lines with a nominal point spacing = 1.4 meters (4.59 feet)

were collected over Erie County, NY (approximately 1044 square miles). Multiple returns were recorded for each laser

pulse along with an intensity value for each return. The data acquisition occurred in missions on April 17, 2008

and April 28, 2008. During the LIDAR campaign, the 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. This is a bare

earth classified data set; points are classified as ground or unclassified. Please note that water points are

sometimes classified as 'Unclassified' and other times as 'Ground'.

LIDAR data is remotely sensed high-resolution elevation data collected by an airborne collection platform.

Using a combination of laser range finding, GPS positioning and inertial measurement technologies; LIDAR instruments

are able to make highly detailed Digital Elevation Models (DEM) of the earth's terrain, man-made structures and vegetation.

This data was collected at a resolution to aid in coastal management decisions including flood plain analysis and mapping.

Original contact information:

Contact Name: Andrew Lucero

Contact Org: Sanborn Map Company, Inc.

Title: Sr. Project Manager

Phone: (719) 265-5645

Email: alucero@sanborn.com

LIDAR data is used for 3D visualization, elevation based analysis and for feature extraction.

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Reflective surface data represents the DEM created by laser energy reflected from the first

surface encountered by the laser pulse. Some energy may continue beyond this initial surface to be reflected by a

subsequent surface as represented by the Last Return data. Intensity information is captured from the Reflective

Surface pulse and indicates the relative energy returned to the sensor as compared to the energy transmitted. The

Intensity image is not calibrated or normalized but indicates differences in energy absorption due to the interaction

of the surface materials with laser energy at the wavelength transmitted by the sensor.

For more information about this data, please refer to the Final Report for Erie County Corridors & Niagara County at:

https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid18/107/supplemental/Final_LiDAR_Report_Niagara_Erie.pdf

Any conclusions drawn from the analysis of this information are not the responsibility of the

Federal Emergency Management Agency (FEMA), Sanborn Map Company, Inc, Medina Consultants, the Office for Coastal Management or its partners.

This data can be obtained on-line at the following URL: https://coast.noaa.gov/dataviewer

The data set is dynamically generated based on user-specified parameters.

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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 XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.2.4.1420

Contracted to meet 1 meter (RMSE) horizontal accuracy.

LiDAR data accuracy determination shall employ the National Standard for Spatial

Data Accuracy (NSSDA). Contracted to meet 18.5cm (RMSE) on open bare terrain and 37.0cm for obscured areas.

LIDAR raster data is visually inspected for completeness to ensure that any gaps between flight lines

or loss of signal represents less than 5% of required collection area. LIDAR is self-illuminating and has minimal cloud

penetration capability. Water vapor in steam plumes or particulates in smoke may cause reflection of LIDAR signals and

loss of elevation information beneath these plumes. Glass structures and roofs may appear transparent to the LIDAR signal

and therefore may not register on the reflective surface. Some asphalt formulations have been shown to absorb topographic

LIDAR wavelength energy resulting in "pitting" of roof surfaces using this material.

All LAS formatted LIDAR data are validated using commercial GIS software to ensure proper

formatting and loading before delivery. This validation procedure ensures that data on delivery media is in correct

physical format and is readable.