Metadata for National Elevation Dataset for Montana, 2002 Metadata for National Elevation Dataset for Montana, 2002

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Identification Information:

Citation:

Originator: U.S. Geological Survey
Publication date: 04/01/2002
Title: National Elevation Dataset for Montana, 2002
Other citation details:: These data were formerly available on the NRIS web page at http://nris.mt.gov/nsdi/nris/el10/dems.html
Online linkage: https://ftpgeoinfo.msl.mt.gov/Data/Spatial/NonMSDI/Elevation/NationalElevationData2002.zip

Browse graphic file name: http://docs.msl.mt.gov/geoinfo/Images/Metadata/el9.gif
Browse graphic file description: Simple image comparing 30 meter and 3 arc-second DEM data

Abstract:

These data were removed from the State Library web site because better data are easily obtainable from the U.S. Geological Survey. Please read about the current data at http://ned.usgs.gov/about.html and use the Data link to obtain the data.

These data are a series of files derived from the National Elevation Dataset that each cover 16 USGS 7.5-minute quadrangles, (a 30x30-minute area), plus the area around those quadrangles required to fill in a rectangle in the coordinate system of the file.

There are four versions of the data:
The "data" folder contains data in USGS DEM format, in Montana State Plane coordinates, NAD83, units meters. The elevations in these files are rounded to the nearest meter. These files were made at a time when ESRI did not support this coordinate system for DEM format files, and modern software may be unable to read the spatial reference from these files.

The "utmdata" folder contains data in USGS DEM format, in UTM zone 11, 12, and 13 coordinates, NAD83, units meters. The elevations in these files are rounded to the nearest meter.

The "fdata" folder contains data in Esri GridAscii format, in Montana State Plane coordinates, NAD83, units meters. The elevations are rounded to the nearest 1/100 of a meter.

The "utmfdata" folder contains data in Esri GridAscii format, in UTM zone 11, 12, and 13 coordinates, NAD83, units meters. The elevations are rounded to the nearest 1/100 of a meter.

The National Elevation Dataset (NED) is a seamless mosaic of best-available elevation data. The 7.5-minute elevation data for the conterminous United States are the primary initial source data. In addition to the availability of complete 7.5-minute data, efficient processing methods were developed to filter production artifacts in the existing data, convert to the NAD83 datum, edge-match, and fill slivers of missing data at quadrangle seams. One of the effects of the NED processing steps is a much-improved base of elevation data for calculating slope and hydrologic derivatives.

The NED for Montana as of 4/1/2002 was donated to the Montana State Library by the Bureau of Land Management Montana/Dakotas office in Billings. The State Library combined the 30- and 10-meter DEMs into a single statewide dataset at 30 meter resolution and extracted data from that dataset to create these data files.

Purpose:

Geospatial elevation data are utilized by the scientific and resource management communities for global change research, hydrologic modeling, resource monitoring, mapping, and visualization applications.

DEMs can be used for creation of slope maps, aspect maps, shaded relief maps, and contour maps; for analysis of hydrography and runoff; for analysis of solar radiation received on the land; for determination of what part of the landscape is visible from various locations; for estimation of volumes of proposed earthworks or reservoirs; and for analysis of difficulty of traversing the terrain.

Time period of content:

Beginning date: 12/10/1998
Ending date: 04/01/2002
Currentness reference: publication date

Status:

Progress: In work
Maintenance and update frequency: As needed

Access constraints: None

Use constraints:

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.

Point of contact:

Montana State Library
PO Box 201800
Helena, Montana 59620-1800
Telephone: 406-444-5354
TDD/TTY telephone: Montana Relay 711
Fax: 406-444-0266
E-Mail: geoinfo@mt.gov

Data Quality Information:

Attribute accuracy report:

See http://gisdata.usgs.net/ned/Accuracy.asp for the U.S. Geological Survey's discussion of the accuracy of the National Elevation Dataset.

The original DEMs that went into the National Elevation Dataset could be classified as Level 1 or Level 2. Level 1 DEMs have elevations whose root mean square accuracy could be as poor as 15 meters. Level 2 DEMs have been smoothed by the USGS for consistency and edited to remove identifiable systematic errors.

Almost all Level 1 DEMs appear to be grainy or irregular in flat areas and look blurry when compared to Level 2 DEMs. Many Level 1 DEMs have stripes or checkerboard patterns running through them. The NED creators have attempted to smooth out the irregularities in these DEMs.

The data are packaged with an image showing the Level of the source DEMs (demicon.gif), a shapefile with information about the source DEMs (dem_index.shp), and a shapefile index of the 30x30-minute data files (file_index.shp). The dem_index.shp file contains a field giving the Root Mean Square error for random points in each DEM whose accuracy was checked.

Completeness report: 30-meter DEMs are available for the entire state of Montana.

Horizontal Positional Accuracy Report:

Each elevation was measured at a pre-calculated coordinate. The coordinates are 30 meters apart.

Vertical positional accuracy report: See attribute accuracy.

Lineage:

Source information:

Originator: U.S. Geological Survey (USGS), EROS Data Center
Publication date: 04/01/2002
Title: National Elevation Dataset
Source scale denominator: 60000
Source contribution: The data set is a re-processed version of these DEMs
Beginning date: 12/10/1998
Ending date: 04/01/2002

Spatial Reference Information:

Horizontal coordinate system definition:

Planar distance units: meters

Geodetic model:

Horizontal datum name: North American Datum of 1983
Ellipsoid name: Geodetic Reference System 80
Semi-major axis: 6378137.0
Denominator of flattening ratio: 298.257

Altitude system definition:

Altitude datum name: National Geodetic Vertical Datum of 1929
Altitude distance units: meters
Altitude encoding method: Implicit coordinate

Distribution Information:

Distributor:

Montana State Library
PO Box 201800
Helena, MT 59620-1800
Telephone: 406-444-5354
TDD/TTY telephone: Montana Relay 711
Fax: 406-444-0266
E-Mail: geoinfo@mt.gov

Resource description: Downloadable Data

Distribution liability:

Metadata Reference Information:

Metadata date: 11/20/2014

Metadata review date: 04/17/2013

Metadata review date: 09/29/2004

Metadata review date: 06/28/2002

Metadata contact:

Montana State Library
PO Box 201800
Helena, Montana 59620-1800
Telephone: 406-444-5354
TDD/TTY telephone: Montana Relay 711
Fax: 406-444-0266
E-Mail: geoinfo@mt.gov