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High Island, Lake Michigan, Michigan

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What does this data set describe?

Title: High Island, Lake Michigan, Michigan

Abstract:

XYZ ASCII format generated from 2001 Lidar survey. These data were collected by the SHOALS (Scanning Hydrographic Operational Airborne Lidar Survey) system which consists of an airborne laser transmitter/receiver capable of measuring 400 soundings per second.

Supplemental_Information:

The system operates from a deHavilland DHC-6 Twin Otter flying at altitudes between 200 and 400 meters with a ground speed of about 100 knots. The SHOALS system also includes a ground-based data processing system for calculating acurate horizontal position and water depth. Lidar is an acronym for LIght Detection And Ranging. The system operates by emitting a pulse of light that travels from an airborne platform to the water surface where a small portion of the laser energy is backscattered to the airborne receiver. The remaining energy at the water's surface propogates through the water column and reflects off the sea bottom and back to the airborne detector. The time difference between the surface return and the bottom return corresponds to water depth. The maximum depth the system is able to sense is related to the complex interaction of radiance of bottom material, incident sun angle and intensity, and the type and quantity of organics or sediments in the water column. As a rule-of-thumb, the SHOALS system should be capable of sensing bottom to depths equal to two or three times the Secchi depth.

US Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise.(ed.), 20011000, High Island, Lake Michigan, Michigan:.

West_Bounding_Coordinate: -085.721000

East_Bounding_Coordinate: -085.697000

North_Bounding_Coordinate: +45.750000

South_Bounding_Coordinate: +45.680000

<http://geopubs.wr.usgs.gov/open-file/of03-120/images/map/hightrout_mapcropL.jpg> (JPEG)

Shaded relief map view of Trout Island Shoals and High Island Reef

Calendar_Date: Aug-2001

Currentness_Reference: Ground Condition

Geospatial_Data_Presentation_Form: XYZ ASCII

Indirect_Spatial_Reference: High Island, Lake Michigan, Michigan

This is a Point data set. It contains the following vector data types (SDTS terminology):

• Point

Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.00004. Longitudes are given to the nearest 0.00004. Latitude and longitude values are specified in Decimal degrees.

The horizontal datum used is WGS84.
The ellipsoid used is WGS84.
The semi-major axis of the ellipsoid used is 6378137.00 meters.
The flattening of the ellipsoid used is 1/0.003352811.

Entity_and_Attribute_Overview:

Each record consists of three fields: longitude, latitude, and depth in meters. Example of records:

 -85.722256740 45.759781770 163.05000
 -85.722256870 45.759849278 163.06000
 -85.722266001 45.759939388 163.22000
 -85.722255177 45.759957268 163.13000
 -85.722269808 45.760020437 163.21000

Entity_and_Attribute_Detail_Citation: none

Who produced the data set?

US Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise.(ed.)

U.S. Army Corps of Engineers JALBCTX
109 St. Joseph Street
Mobile, Alabama 36602
USA

(334) 694-3721 (voice)
(334) 690-3464 (FAX)

Why was the data set created?

The purpose of the survey was to provide bathymetry and albedo dat for utilization in habitat studies.

How was the data set created?

None (source 1 of 1)

U.S. Army Corps of Engineers JALBTCX, 20011000, High Island, Lake Michigan, Michigan.

Type_of_Source_Media: CD-ROM

Source_Contribution: SHOALS

Date: Sep-2001 (process 1 of 1)

The SHOALS airborne system acquires a tremendous volume of raw data during a single mission. The lidar data are unique and require a specialized Data Processing System (DPS) for post-processing. The DPS main funcions 1) import airborne data stored on high density data tape; 2) perform quality control checks on initial depths and horizontal positions; 3) provide display and edit capabilities; 4) calculate depth and position (XYZ) values for each sounding; and 5) output final positions and depths for each sounding.

US Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise.(ed.), 20011000, Boulder Reef, Lake Michigan, Michigan.

Online Links:

• <http://walrus.wr.usgs.gov/infobank/t/t101lm/html/t-1-01-lm.meta.html>

How reliable are the data; what problems remain in the data set?

SHOALS has demonstrated capabilities that meet US Army Corps of Engineers Hydrographic Survey accuracy requirements for Class 1 surveys and the International Hydrographic Organization nautical charting standards for Order 1.

+/- 3 meters (1 sigma)

+/- 15 cm (1 sigma)

Complete

None

How can someone get a copy of the data set?

Access_Constraints: None

Use_Constraints:

Acknowledgement of the U.S. Army Engineer Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBCTX) would be appreciated in products derived from these data.

U.S Geological Survey
c/o Peter Barnes
MS999 345 Middlefield Road
Menlo Park, CA 94025

916-329-5265 (voice)

These data not intended for navigational purposes.

Although these data have been used by the U.S. Geological Survey, U.S. Department of the Interior, these data and information are provided with the understanding that they are not guaranteed to be usable, timely, accurate, or complete. Users are cautioned to consider carefully the provisional nature of these data and information before using them for cisions that concern personal or public safety or the conduct of business that involves substantial monetary or operational consequences. Conclusions drawn from, or actions undertaken on the basis of, such data and information are the sole responsibility of the user.

Neither the U.S. Government nor any agency there of, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any data, software, information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights.

Trade, firm, or product names and other references to non-USGS products and services are provided for information only and do not constitute endorsement or warranty, express or implied, by the USGS, USDOI, or U.S. government, as to their suitability, content, usefulness, functioning, completeness, or accuracy.

Availability in digital form:

Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 30-Jan-2003
Last Reviewed: Feb-2003

Metadata author:

USGS
c/o Kristen Lee
Physical Science Technican
USGS, MailStop 999, 345 Middlefield Road
Menlo Park, CA 94025-3561
USA

(650) 329-5260 (voice)
(650) 329-5411 (FAX)
kmlee@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata ("CSDGM version 2") (FGDC-STD-001-1998)