Identification Information

Title Roy 1:100000 Quad Hydrography DLGs

Date 2009-02-17

Date Type Publication

Cited Responsible Party

Organization Name U.S. Geological Survey or another mapping agency in cooperation with USGS.

Role identify

Presentation Form vector digital data

Abstract Digital line graph (DLG) data are digital representations of cartographic information. DLG's of map features are converted to digital form from maps and related sources. Intermediate-scale DLG data are derived from USGS 1:100,000-scale 30- by 60-minute quadrangle maps. If these maps are not available, Bureau of Land Management planimetric maps at a scale of 1: 100,000 are used. Intermediate-scale DLG's are sold in five categories: (1) Public Land Survey System; (2) boundaries (3) transportation; (4) hydrography; and (5) hypsography. All DLG data distributed by the USGS are DLG - Level 3 (DLG-3), which means the data contain a full range of attribute codes, have full topological structuring, and have passed certain quality-control checks.

Purpose DLG's depict information about geographic features on or near the surface of the Earth, terrain, and political and administrative units. These data were collected as part of the National Mapping Program.

Status In work

Point of Contact

Individual Name

Organization Name USGS

Position Name Clearinghouse Manager

Role Point of contact

Voice 703-648-4543

Facsimile

Address

Delivery Point 508 National Center
City Reston
Administrative Area VA
Postal Code 20192
Country USA

Electronic Mail Address

Maintenance and Update Frequency Irregular

Descriptive Keywords digital line graph, DLG, hydrography, transportation, boundaries, U.S. Public Land Survey System, hypsography

Access Constraints None

Use Constraints None. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data.

Language English

Topic Category inlandWaters

Extent

Geographic Bounding Box

West Bound -106.000031
East Bound -102.999908
North Bound 37.000141
South Bound 35.499973

Temporal Extent

Beginning Position 1987-06-19
Ending Position Present

Data Quality Information

Attribute Accuracy Report

Report Refer to Positional_Accuracy element.

Quantitative Attribute Accuracy Assessment

Attribute Accuracy Value
Attribute Accuracy Explanation

Horizontal Positional Accuracy Report

Report For Digital Revision Status = Not revised:

Quantitative Horizontal Positional Accuracy Assessment

Horizontal Positional Accuracy Value
Horizontal Positional Accuracy Explanation

Vertical Positional Accuracy Report

Report For Hypsography and Hydrography Only: For Digital Revision Status = Not revised:

Quantitative Vertical Positional Accuracy Assessment

Vertical Positional Accuracy Value
Vertical Positional Accuracy Explanation

Logical Consistency Report Topological requirements include: lines must begin and end at nodes, lines must connect to each other at nodes, lines do not extend through nodes, left and right areas are defined for each line element and are consistent throughout the file, and the lines representing the limits of the file (neatline) are free of gaps. The tests of logical consistency were performed by the USGS PROSYS program. The neatline was generated by connecting the four corners of the digital file, as established during initialization of the digital file. All data outside the enclosed region were ignored and all data crossing these geographically straight lines were clipped at the neatline. Data within a specified tolerance of the neatline were snapped to the neatline. Neatline straightening aligned the digitized edges of the digital data with the generated neatline, that is, with the longitude/latitude lines in geographic coordinates. All internal areas were tested for closure using PROSYS.

Completeness Report For Digital Revision Status = Not revised Data completeness reflects the content of the source quadrangle. Features may have been eliminated or generalized on the source graphic, due to scale and legibility constraints. For Digital Revision Status = Limited Update This file has undergone limited update digital revision. The file contains only (1) those features that are photoidentifiable on monoscopic source, supplemented with limited ancillary source, and (2) those features, present on the original source quadrangle, that can not be reliably photoidentified but that are not considered particularly prone to change. For Digital Revision Status = Standard Update This file has undergone standard update digital revision. The data completeness of this file meets NMD standards for feature content.

Lineage

Source Information

Source Citation

Source Scale Denominator 100000

Type of Source Media stable-base material

Source Time Period of Content

Beginning Position 1987-06-19
Ending Position Present
Source Currentness Reference ground condition

Source Citation Abbreviation MAP1

Source Contribution spatial and attribute information

Process Step

Process Description For Digital Revision Status = Not digitally revised: This Digital Line Graph was digitized from the USGS source quadrangle, by either the National Mapping Division, one of their cooperators, or one of their contractors. The digital data were produced by one of the following methods: - scanning a stable-based copy of the graphic materials. The scanning process captured the digital data at a scanning resolution of at least 0.001 inches; the resulting raster data were vectorized and then attributed on an interactive editing station. - scanning the paper map. The scanning process captured the digital data at a scanning resolution of at least 0.001 inches; the resulting raster data were vectorized and then attributed on an interactive editing station. - scanning a stable-based copy of the graphic materials. The resulting raster data were then manually digitized and attributed on an interactive editing station. The resolution of the digital data is at least 0.001 inches. - scanning the paper map. The resulting raster data were then manually digitized and attributed on an interactive editing station. The resolution of the digital data is at least 0.001 inches. - manually digitizing from a stable-based copy of the graphic material using a digitizing table to capture the digital data at a resolution of at least 0.001 inches; attribution was performed either as the data were digitized, or on an interactive edit station after the digitizing was completed. - manually digitizing from the paper map using a digitizing table to capture the digital data at a resolution of at least 0.001 inches; attribution was performed either as the data were digitized, or on an interactive edit station after the digitizing was completed. The determination of the DLG production method was based on various criteria, including feature density, feature symbology, and availability of production systems. Four control points corresponding to the four corners of the quadrangle were used for registration during data collection. An eight parameter projective transformation was performed on the coordinates used in the data collection and editing systems to register the digital data to the internal coordinates used in PROSYS, and a four parameter linear transformation was performed from the PROSYS internal coordinates to Universal Transverse Mercator (UTM) grid coordinates. The DLG data were checked for position by one or more of the following processes: - comparing plots of the digital data to the graphic source. - comparing the digital data to the digital raster scan. DLG data classification was checked by at least one of the following processes. - comparing plots of the digital data to the graphic source - comparing the digital data to the digital raster scan.
Source Used Citation Abbreviation MAP1
Process Date Unknown
Process Time
Process Contact

Roy 1:100000 Quad Hydrography DLGs

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