Metadata for Flathead Basin 2009 2-Foot Contours, Generalized

Identification Information
Data Quality Information
Spatial Data Organization Information
Spatial Reference Information
Entity and Attribute Information
Distribution Information
Metadata Reference Information

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Identification Information:

Citation:

Originator: Watershed Sciences
Publication date: 11/2010
Title: Flathead Basin 2009 2-Foot Contours, Generalized
Online linkage: http://geoinfo.montanastatelibrary.org/data/flatheadbasin_mapping_project_2009/contour_data/shapefiles/

Abstract:

2-foot topographic contours of the Flathead Basin, including the Flathead Valley north of Flathead Lake and the immediate areas around Whitefish Lake, Flathead Lake, Swan Lake, and Polson. These contours were derived by automated methods from LiDAR point cloud data collected between September 22 and September 29, 2009.

The contour data provided by Watershed Sciences contained a very large number of vertices, with many line segements whose ground length were less than an inch. This data was generalized at the State Library to reduce the overall file size by over 75 percent, while still retaining line fidelity such that no vertex in the original data is more that 1.5 inches, on the ground, from its representation in this data set.

Purpose:

Elevation data to be used for floodplain delineation and other landscape analyses.

Time period of content:

Beginning date: 09/22/2009
Ending date: 09/29/2009
Currentness reference: ground condition

Status:

Progress: Complete
Maintenance and update frequency: None planned

Access constraints: none

Use constraints:

The Montana State Library Geographic Information Services provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time.

Point of contact:

Stephen Story
Montana DNRC Water Resources Division
1424 9th Avenue
Helena, Montana 59620-1601
Telephone: 406-444-6664
E-Mail: sestory@mt.gov

Data Quality Information:

Quantitative horizontal positional accuracy assessment:

Vertical positional accuracy report:

The vertical accuracy of the LiDAR data is described as the mean and standard deviation (sigma) of divergence of LiDAR point coordinates from 4229 ground survey point coordinates. The root mean square error (RMSE) for vertical accuracy of these control points is provided.

Quantitative vertical positional accuracy assessment:

Vertical positional accuracy value: 3 centimeters

Lineage:

Source information:

Beginning date: 09/22/2009
Ending date: 09/29/2009

Process step:

The LiDAR survey used a Leica ALS50 Phase II laser system. For the Flathead Basin survey site, the sensor scan angle was plus or minus 15 degrees from nadir with a pulse rate designed to yield an average native density (number of pulses emitted by the laser system) of 4 points per square meter over terrestrial surfaces.

A terrain model was produced for the study area. The digital elevation modelswas created from a triangulated irregular network (TIN) of ground classified LiDAR points, however the elevation model has hydrographic feature breaklines enforced.

3Di West (GeoTerra Mapping Group) collected breaklines for the Flathead basin study area using photogrammetric techniques. The photogrammetric breaklines were used to supplement the LiDAR data in creation of a hydrologically enforced ground model. Hard breaklines were draped to the elevation of the LiDAR derived ground model to co-register the elevation of the photogrammetric breakline with the LiDAR ground class. The stream breaklines were implemented as soft breaklines, and used to detect culverts. Points previously classified as ground above culverts in the LiDAR data were re-classed as non-ground, enabling stream channels to continue flow. Other breaklines, such as top of bank, were used to aid ground classification, and in areas where the LiDAR did not collect a ground point, ground points were added along the breakline.

The LiDAR DEM was hydrologically enhanced using the photogrammetrically derived breaklines. The breaklines were implemented in the LiDAR data model differently depending on the feature represented. The implementation for each feature is designed to provide the most accurate and hydrologically correct ground model.

Contour key points were classed out of the ground model every 10 feet to provide more manageable dataset to work with (provided no significant change in Z). Contours were produced through TerraModeler with a Z tolerance of .33 feet. The same breakline rules and resulting ground class for the hydrologically enforced ground model were used as the basis for contour creation. Contour lines (2 ft.) were derived from ground-classified LiDAR point data using Terrasolid LiDAR processing tools in Microstation v.8.01.

Process step:

Use the "Simplify Line" command from ESRI ArcToolbox to generalize the data with a tolerance of 1.5 inches.

Spatial Data Organization Information:

Point and vector object information:

SDTS object type: String

SDTS object count: 2387627

Spatial Reference Information:

Horizontal coordinate system definition:

Grid coordinate system name: State Plane Coordinate System

SPCS zone identifier: 2500

Lambert conformal conic:

Standard parallel: 45.000000
Standard parallel: 49.000000
Longitude of central meridian: -109.500000
Latitude of projection origin: 44.250000
False easting: 600000.000000
False northing: 0.000000

Planar distance units: U.S. Survey Feet

Geodetic model:

Horizontal datum name: D_North_American_1983_HARN
Ellipsoid name: Geodetic Reference System 80
Semi-major axis: 6378137.000000
Denominator of flattening ratio: 298.257222

Altitude system definition:

Altitude datum name: NAVD 88 Geoid03
Altitude resolution: 0.000100
Altitude distance units: Feet
Altitude encoding method:: Explicit elevation coordinate included with horizontal coordinates

Entity and Attribute Information:

Entity type label:

Contour

Attribute label: OBJECTID

Attribute definition: Internal feature number.

Attribute label: Shape

Attribute definition: Feature geometry.

Attribute label: elevation

Attribute definition: Elevation of line in feet

Attribute label: Shape_Length

Attribute definition: Length of feature in feet

Distribution Information:

Distributor:

Montana State Library
PO Box 201800
Helena, MT 59620-1800
Telephone: 406-444-5354
E-Mail: geoinfo@mt.gov

Resource description: Downloadable Data

Distribution liability:

The Montana State Library provides this product/service for informational purposes only. The Library did not produce it for, nor is it suitable for legal, engineering, or surveying purposes. Consumers of this information should review or consult the primary data and information sources to ascertain the viability of the information for their purposes. The Library provides these data in good faith but does not represent or warrant its accuracy, adequacy, or completeness. In no event shall the Library be liable for any incorrect results or analysis; any direct, indirect, special, or consequential damages to any party; or any lost profits arising out of or in connection with the use or the inability to use the data or the services provided. The Library makes these data and services available as a convenience to the public, and for no other purpose. The Library reserves the right to change or revise published data and/or services at any time.

Standard order process:

Digital form:

Format name: ESRI shapefile
Online option:

Metadata Reference Information:

Metadata date: 10/31/2013

Metadata review date: 05/2010

Metadata contact:

Montana State Library
PO Box 201800
Helena, Montana 59620-1800
Telephone: 406-444-5354
E-Mail: geoinfo@mt.gov