- Identification_Information:
- Citation:
- Citation_Information:
- Originator: U.S. Geological Survey (USGS) EROS Data Center (EDC)
- Publication_Date:
- Title: Digital Raster Graphic ID:
- Geospatial_Data_Presentation_Form: map
- Series_Information:
- Series_Name: USGS Digital Raster Graphics
- Issue_Identification:
- Digital Raster Graphics (DRGs) are scanned color images of USGS topographic maps.
- Publication_Information:
- Publication_Place: Sioux Falls
- Publisher: U.S. Geological Survey EROS Data Center
- Other_Citation_Details:
- Earth Science Information Centers (ESIC) offer 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.
- Online_Linkage:
- http://earthexplorer.cr.usgs.gov/
- Description:
- Abstract:
- 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.
- Purpose:
- The DRG is used for validating digital line graphs (DLGs) and for DLG 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.
- Supplemental_Information:
- Digital raster graphic (DRG) data on CD-ROM are being 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.
- Time_Period_of_Content:
- Time_Period_Information:
- Range_of_Dates_Times:
- Beginning_Date:
1996
- Ending_Date: Present
- Currentness_Reference: ground condition
- Status:
- Progress: In work
- Maintenance_and_Update_Frequency: As needed
- Spatial_Domain:
- Bounding_Coordinates:
- West_Bounding_Coordinate:
-124.7333
- East_Bounding_Coordinate: -67.9500
- North_Bounding_Coordinate:
49.3833
- South_Bounding_Coordinate: 24.5333
- Keywords:
- Theme:
- Theme_Keyword_Thesaurus: GCMD Parameter Keywords
- Theme_Keyword: EARTH SCIENCE --> LAND SURFACE --> Topography --> Contours
- Theme_Keyword: EARTH SCIENCE --> LAND SURFACE --> Topography --> Landforms
- Theme_Keyword: EARTH SCIENCE --> LAND SURFACE --> Topography --> Relief
- Theme_Keyword: U.S. Public Land Survey System
- Theme_Keyword: aerial photograph
- Theme_Keyword: cartography
- Theme_Keyword: cities
- Theme_Keyword: county boundaries
- Theme_Keyword: earth
- Theme_Keyword: EDC
- Theme_Keyword: EROS
- Theme_Keyword: hydrography
- Theme_Keyword: lakes
- Theme_Keyword: manmade features
- Theme_Keyword: mapping
- Theme_Keyword: orthophoto
- Theme_Keyword: orthophotoquad
- Theme_Keyword: photography
- Theme_Keyword: railroads
- Theme_Keyword: rivers
- Theme_Keyword: roads
- Theme_Keyword: topography
- Theme_Keyword: U.S. Public Land Survey System
- Theme_Keyword: USGS
- Theme_Keyword: water
- Place:
- Place_Keyword_Thesaurus: GCMD Location Keywords
- Place_Keyword: North America
- Place_Keyword: US
- Place_Keyword: United States
- Temporal:
- Temporal_Keyword_Thesaurus: None
- Temporal_Keyword: true ground conditions
- Access_Constraints: None
- Use_Constraints:
- Acknowledgement of the Geological Survey would be appreciated in products derived from these data.
- Point_of_Contact:
- Contact_Information:
- Contact_Organization_Primary:
- Contact_Organization: U.S. Geological Survey EROS Data Center
- Contact_Person: Customer Services Representative
- Contact_Position: Customer Services Representative
- Contact_Address:
- Address_Type: mailing and physical address
- Address: U.S. Geological Survey EROS Data Center
- City: Sioux Falls
- State_or_Province: SD
- Postal_Code: 57198-0001
- Country: USA
- Contact_Voice_Telephone: 605-594-6151
- Contact_TDD_TTY_Telephone: 605-594-6933
- Contact_Facsimile_Telephone: 605-594-6589
- Contact_Electronic_Mail_Address: custserv@usgs.gov
- Hours_of_Service: 0800 - 1600 CT
- Contact_Instructions:
- http://edcwww.cr.usgs.gov/eros-home.htm
- Security_Information:
- Security_Classification_System: none
- Security_Classification: unclassified
- Data_Quality_Information:
- Logical_Consistency_Report:
- 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.
- Completeness_Report:
- 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.
- Positional_Accuracy:
- Horizontal_Positional_Accuracy:
- Horizontal_Positional_Accuracy_Report:
- 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.
- Quantitative_Horizontal_Positional_Accuracy_Assessment:
- Horizontal_Positional_Accuracy_Value:
- Horizontal_Positional_Accuracy_Explanation:
- DRGs retain the horizontal 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.
- Vertical_Positional_Accuracy:
- Vertical_Positional_Accuracy_Report: The vertical positional accuracy of a DRG is referenced in the DRG collar
- Lineage:
- Source_Information:
- Source_Citation:
- Citation_Information:
- Originator: U.S. Geological Survey
- Publication_Date: unknown
- Title: USGS Topographic maps
- Geospatial_Data_Presentation_Form: map
- Other_Citation_Details:
- 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.
- Source_Scale_Denominator: 250000
- Type_of_Source_Media: paper
- Source_Time_Period_of_Content:
- Time_Period_Information:
- Range_of_Dates_Times:
- Beginning_Date:
0000
- Ending_Date: present
- Source_Currentness_Reference: ground condition
- Source_Citation_Abbreviation: USGS Topo
- Source_Contribution:
- 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
- Process_Step:
- Process_Description:
- 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.
- Source_Used_Citation_Abbreviation: map1
- Process_Date: 0000
- Process_Contact:
- Contact_Information:
- Contact_Organization_Primary:
- Contact_Organization: Rolla-ESIC U.S. Geological Survey
- Contact_Position: Customer Services Representative
- Contact_Address:
- Address_Type: mailing and physical address
- Address: 1400 Independence Rd., MS231
- City: Rolla
- State_or_Province: MO
- Postal_Code: 65401-2602
- Country: USA
- Contact_Voice_Telephone: 573-308-3577
- Contact_Facsimile_Telephone: 573-308-3652
- Contact_Electronic_Mail_Address: esic@mcmcmail.er.usgs.gov
- Contact_Instructions:
- http://mcmcweb.er.usgs.gov/drg/
- Spatial_Data_Organization_Information:
- Direct_Spatial_Reference_Method: Raster
- Raster_Object_Information:
- Raster_Object_Type: Pixel
- Row_Count:
- Column_Count: