Metadata for Montana 1:24,000 scale UTM DRG Quadrangles

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: U.S. Geological Survey
Publication date: 06/23/1998
Title: Montana 1:24,000 scale UTM DRG Quadrangles
Online linkage: http://apps.msl.mt.gov/Geographic_Information/Data/Topographic/topo24KUTMTiffIndividual.aspx

Browse graphic file name: http://docs.msl.mt.gov/geoinfo/Images/Metadata/drg.gif

Abstract:

U.S. Geological Survey (USGS) Digital Raster Graphics (DRGs) are scanned, georeferenced images of USGS topographic maps. These original TIFF image files from the USGS include the collar information and are georeferenced to the UTM grid.

This document is a summary of all the original UTM 1:24,000 scale DRG files on the Montana State Library web site. Each individual DRG file comes with an accompanying metadata document that gives the quadrangle name and date. Each file is in UTM coordinates. Quadrangles west of the 114th meridian are in zone 11, quads between the 114th and 108th meridians are in zone 12, and quads east of the 108th meridian are in zone 13.

We received these map images in 1998. The files have not been updated since that time, and many of the maps are more than 50 years old. Newer versions of many of these images may be available for free download at the USGS Store. A shapefile index of the map dates is available at ftp://ftp.geoinfo.msl.mt.gov/Data/Spatial/NonMSDI/Raster/TopoQuads1998/24k/DRG_24k_Index.zip.

Time period of content:

Beginning date: 1950
Ending date: 1996
Currentness reference: Publication Date

Status:

Progress: Complete

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: 406-444-4799
Fax: 406-444-0266
E-Mail: geoinfo@mt.gov

Data set credit:

Most DRGs in Montana were produced through and Innovative Partnership agreement between the Land Information Technology Company, Ltd., of Aurora, CO and the USGS.

Data Quality Information:

Attribute accuracy report:

A DRG is an 8-bit color image that employs a color pallette to ensure uniform colors throughout a particular DRG series. All DRG's within a series must have the same RGB value.

Completeness report:

DRGs are faithfully reproduced digital images of the original source maps. Some differences may be detected between the source graphics used and the DRGs due to the RGB values assigned that particular color. The intent is to re-create those colors as near as possible. Data completeness for DRG files reflect content of the source graphics. Features may have been eliminated or generalized on the source graphics due to scale and legibility constraints. For information on collection and inclusion criteria, see U.S. Geological Survey, 1994, Standards for 1:24,000-Scale Digital Line Graphs and Quadrangle Maps: National Mapping Program Technical Instructions and U.S. Geological urvey, 1994, Standards for Digital Line Graphs: National Mapping Program.

Horizontal Positional Accuracy Report:

While the datum of the published maps are retained to be consistent with other USGS digital data, the images are cast on the UTM and may be inconsistent with the credit notes on the image collars. Approximate horizontal accuracy is 12 meters, assuming source data meets National Map Accuracy Standards.

Vertical positional accuracy report:

Refer to the DRG collars for information about vertical positional accuracy.

Lineage:

Source information:

Originator:: National Mapping Division
U.S. Geological Survey
Publication date: 1940
Title: 1:24,000-scale 7.5 minute quadrangles
Source scale denominator: 24000
Type of source media: paper
Source contribution: The data set is an image of this source.
Beginning date: 1940
Ending date: 1996

Process step:

The production procedures, instrumentation, hardware, and software used in the collection of standard DRG products vary depending on systems used at the contract, cooperator or USGS production sites. The majority of DRG data sets are acquired through government contract. The process step describes, in general, the process used in the production of standard DRG data sets.
1. Production of a DRG begins with the scanning of a paper 7.5-minute topographic map (map1) on a high-resolution scanner. Scanning resolutions range from 500 - 1000 dpi with the output file running between 160-300 mb.
2. Removal of screens (descreening) and color quantization to reduce the number of colors also takes place during the scanning phase.
3. The raw scan file is then transformed and georeferenced using UTM coordinates of the sixteen 2.5-minute grid ticks, which are obtained using the in-house produced program COORDAT and stored in a ground control file. Those sixteen 2.5-minute ticks are interactively visited and assigned their respective UTM coordinates. USGS program XSHAPES4 then performs a piecewise linear rubber sheet transformation.
4. An output resolution of 2.4 meters (8.2 feet) is chosen in order to resample the file to 250 dpi.
5. The image file is converted to a TIFF and further reduced by converting the file to a run length encoding Packbits compression(type 32773).
6. The color palette of the compressed DRG is then standardized by replacing the original RGB values assigned during the scanning process with standard RGB value combinations using the in-house produced TIFFREMAP program.
7. Prior to archiving the DRG undergoes the following quality assurance procedures:
a. The color index values of each DRG are checked to ensure the RGB combinations are consistent with the standardized color palette.
b. All DRG files are inspected to ensure that they are geometrically consistent with normal map presentation.
c. Selected DRG's are checked to ensure that data elements in the DRG metadata file correspond to the map collar information and to the information in the associated image file.
d. Selected DRG's are checked for georeferencing accuracy by comparing the book value of latitude and longitude tick marks with corresponding tick intersections in the DRG image.
e. Transformations are checked on selected DRG's by comparing the positions of well defined points, such as UTM grid intersections in the graphic product, with the corresponding image points in the DRG.

USGS DRG production specifications are available on request from the National Mapping Division and Mid-Continent Mapping Center by contacting:
Rolla-ESIC
U.S. Geological Survey
1400 Independence Rd., MS231
Rolla, MO 65401-2602
Phone (573)308-3500
Facsimile (573)308-3615
E-mail to mcmcesic@usgs.gov
World Wide Web: http://mcmcweb.er.usgs.gov/drg/


Process date: 1996

Spatial Data Organization Information:

Raster object information:

Raster object type: Pixel
Row count: 6800
Column count: 4900

Spatial Reference Information:

Horizontal coordinate system definition:

Grid coordinate system name: Universal Transverse Mercator

UTM zone number: 12

Transverse mercator:

Scale factor at central meridian: 0.9996
Longitude of central meridian: -111.0
Latitude of projection origin: 0.0
False easting: 500000
False northing: 0.0

Planar distance units: meters

Geodetic model:

Horizontal datum name: North American Datum of 1927
Ellipsoid name: Clarke 1866
Semi-major axis: 6378206.4
Denominator of flattening ratio: 294.98

Altitude system definition:

Altitude datum name: NGVD29
Altitude resolution: 20
Altitude distance units: FEET
Altitude encoding method: Images of contours

Entity and Attribute Information:

Entity and attribute overview:: Each raster entity or pixel contains a color index from 0 through 12 referencing a color palette of RGB values from 0 through 255 in which the standard colors used in the DRG are defined.

USGS DRG Color Palette
Number Color Red Green Blue
0 Black 0 0 0
1 White 255 255 255
2 Blue 0 151 164
3 Red 203 0 23
4 Brown 131 66 37
5 Green 201 234 157
6 Purple 137 51 128
7 Yellow 255 234 0
8 Light Blue 167 226 226
9 Light Red 255 184 184
10 Light Purple 218 179 214
11 Light Grey 209 209 209
12 Light Brown 207 164 142
Entity and attribute detail citation: Draft Standards for Digital Raster Graphic.

Distribution Information:

Distributor:

Montana State Library
PO Box 201800
Helena, MT 59620-1800
Telephone: 406-444-5354
TDD/TTY telephone: 406-444-4799
Fax: 406-444-0266
E-Mail: geoinfo@mt.gov

Resource description: Downloadable Data

Distribution liability:

Standard order process:

Digital form:

Format name: TIFF
Online option:

Metadata Reference Information:

Metadata date: 10/30/2013

Metadata review date: 09/19/2013

Metadata review date: 04/17/2013

Metadata review date: 09/29/2004

Metadata review date: 06/23/1998

Metadata contact:

Montana State Library
PO Box 201800
Helena, Montana 59620-1800
Telephone: 406-444-5354
TDD/TTY telephone: 406-444-4799
Fax: 406-444-0266
E-Mail: geoinfo@mt.gov