USGS Earth Resources Observation & Science Center (EROS)
19981101
Digital Raster Graphic: TETON VILLAGE , WY
map
USGS Digital Raster Graphics
Digital Raster Graphics (DRGs) are scanned color
images of USGS topographic maps.
nationwide information and sales service for USGS map products and earth science
publications. For additional information, contact any USGS Earth Science Information
Center (ESIC), or call 1-888-ASK-USGS.
A digital raster graphic (DRG) is a scanned image of a U.S. Geological
Survey (USGS) topographic map. The scanned image includes all map collar
information. The image inside the map neatline is georeferenced to the surface of
the Earth. The DRG can be used to collect, review, and revise other digital data
especially digital line graphs (DLG). When the DRG is combined with other digital
products, such as digital orthophoto quadrangles (DOQ) or digital elevation models
(DEM), the resulting image provides additional visual information for the extraction
and revision of base cartographic information. The USGS is producing DRGs of the
1:24,000-, 1:25,000-, 1:63,360- (Alaska), 1:100,000-, and 1:250,000-scale topographic
map series.
data collection and revision. The DRG can help assess the completeness of digital
data from other mapping agencies. It can also be used to produce "hybrid"
products. These include combined DRGs and DOQs for revising and collecting digital
data, DRGs and DEMs for creating shaded-relief DRGs and combinations of DRG, DOQ, and
DLG data. Although a standard DRG is an effective mapping tool, its full potential
for digital production is realized in combination with other digital data.
produced by the U.S. Geological Survey (USGS) through an Innovative Partnership
agreement with The Land Information Technology Company Ltd. of Aurora, CO. This
series includes DRG's of USGS standard series quadrangle maps of the United States,
its Trusts, and Territories.
19970318
19970318
ground condition
As needed
-110.875
-110.75
43.625
43.5
GCMD Parameter Keywords
aerial photograph
cartography
cities
county boundaries
earth
EDC
EROS
hydrography
lakes
manmade features
mapping
orthophoto
orthophotoquad
photography
railroads
rivers
roads
topography
U.S. Public Land Survey System
USGS
water
EARTH SCIENCE --> LAND SURFACE --> Topography -->
Landforms
Relief
Contours
GCMD Location Keywords
North America
United States
US
None
true ground conditions
None
Acknowledgement of the Geological Survey would be appreciated in
products derived from these data.
U.S. Geological Survey Earth Resources Observation
and Science (EROS) Center
Customer Service
mailing and physical address
U.S. Geological Survey
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
lta@usgs.gov
0800 - 1600 CT, M-F, -6 h GMT
Online Ordering: Once you have filled out and submitted
the online ordering form found at http://earthexplorer.usgs.gov, it is forwarded to
Customer Services at the USGS National Center for Earth Resources Observation &
Science (EROS) via the Earth Explorer system. EROS uses a secure credit card server
that will encrypt your sensitive information and pass it from your browser to the
EROS web server. Mail Ordering: First obtain the ordering information from Earth
Explorer. Mail this information, along with your payment (check or purchase/money
order), to USGS, EROS,
none
unclassified
The USGS DRG is produced with the intention of
replicating as close as possible the original source map. Users of the DRG will
note, however, that a certain amount of "noise" can be discerned when small
areas are blown up or viewed under zoomed-in conditions. This noise is in the form
of random specks or pixels of color and halos due to any number of factors, such as
the quality of the source, the use of screens and patterns on the litho, and the
unevenness of ink due to saturation and absorption. Discontinuities or breaks in
linear features may also be present and are due to improper calibration or usage of
the scanner, the condition of the source, and resampling. Descreening, quantizing,
and noise filtering are methods used to reduce noise, which, besides creating a more
aesthetically pleasing image, have the added benefit of reducing the size of the
image file. Removal of lithographic screen patterns is preferred but not required.
Image completeness is checked by visually inspecting a
sampling of DRGs. Each selected DRG is examined for gaps (missing data) in the main
body of the map, the map collar, the overedge areas, and any insets.
A random sampling of DRGs is accuracy
tested. The accuracy test is performed by comparing the positions of UTM grid
intersections on the source graphic against the corresponding location on the digital
image. A visual inspection determines whether those coordinates fall within the
pixels that define a grid tick. DRGs duplicate the horzontal accuracy of its source.
accuracy of the source maps. Most USGS printed maps contain the National Map
Accuracy Standards (NMAS) note in the collar area. The NMAS states that for maps on
publication scales of 1:20,000 or smaller, no more than 10 percent of the points
tested shall be in error by more than 1/50 inch measured on the publication scale.
Test points must be "well-defined", that is, easily visible or recoverable
on the ground. For DRGs this accuracy statement applies only to that area of the DRG
that falls within the neatline of the source map (excluding inset areas). Overedge
areas falling outside the transformation boundary area (the map neatline) can exhibit
anomalies or discrepancies. These anomalies also will appear in the map inset areas
and in the map collar. For maps without the NMAS note, the horizontal accuracy is
unknown. However, the DRG will retain the accuracy of the source map.
The vertical positional accuracy of a DRG
is referenced in the DRG collar
U.S. Geological Survey
unknown
USGS Topographic maps
map
The source for DRGs are the standard quadrangle
format USGS topographic maps as described in the Federal Geographic Data Committee
"Manual of Federal Geographic Data Products". They include 1:20,000-,
1:24,000-, 1:25,000-, 1:30,000-, 1:63,360-, 1:100,000- and 1:250,000-scale
topographic maps. Included in the 1:24,000- and 1:25,000-scale series are
provisional (P) maps and color orthophotomaps.
24000
paper
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19910701
ground condition
USGS Topo
The standard area of coverage of a DRG is the entire area
printed on a USGS standard series topographic map including the map collar, any
overedge areas, and insets. These standard series maps include:
7.5-minute map series: Conterminous United States, Hawaii, and limited areas of
Alaska at 1:24,0000 and 1:25,000 scale.
7.5- by 15-minute map series: Covers limited areas of the conterminous United States
at 1:25,000 scale.
30- by 60-minute map series: Conterminous United States
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 500-1,000 dpi with an output file of 160-300 Mb in size. Removal of
screens (descreening) and color quantization to reduce the number of colors also
takes place during the scanning phase.
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. The USGS program
XSHAPES4 then performs a piecewise linear rubber sheet transformation.
An output resolution of 2.4 meters (8.2 feet) is chosen to resample the file to 250
dpi. The image file is converted to a TIFF 6.0 image and further reduced by
converting the file to a run length encoded PackBits compression (type 32773).
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.
Raster_Object_Information Raster_Object_Type
unknown
Each raster entity or pixel contains a digital
number referencing a color palette of RGB values. Pixel resolution X is 2.4384 and
pixel resolution Y is 2.4384
U.S. Geological Survey Earth Resources Observation
and Science (EROS) Center
mailing and physical address
Customer Services, U.S. Geological Survey
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
lta@usgs.gov
0800 - 1600 CT, M-F, -6 h GMT
<URL: http://edc.usgs.gov/eros-home.html>
Although these data have been processed successfully on
a computer system at the USGS, no warranty expressed or implied is made by the USGS
regarding the use of the data on any other system, nor does the act of distribution
constitute any such warranty.
prerequisite for viewing data in digital form.
Metadata_Review_Date as needed
U.S. Geological Survey Earth Resources Observation
and Science (EROS) Center
Archive Management
mailing and physical address
U.S. Geological Survey
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
lta@usgs.gov
0800 - 1600 CT, M-F, -6 h GMT
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998
Version 2.0
FGDC-STD-001-1998, Version 2
local time
None
None
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Unclassified
None