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DCW Data Quality, Lines

Identification Information
Citation
Originator
National Imagery and Mapping Agency (now National Geospatial-Intelligence Agency)
Publication Date
19920701
Title
DCW Data Quality, Lines
Edition
First
Geospatial Data Presentation Form
vector digital data
Publication Information
Publication Place
Fairfax, VA
Publisher
National Imagery and Mapping Agency
Online Linkage
https://hgl.harvard.edu/catalog/harvard-dcw-dq-line
Abstract
This datalayer is a polyline coverage representing data quality features throughout DCW (Digital Chart of the World) geographic coverage as of 1992. The Data Quality Line Related Attribute Table contains text describing specific conditions occurring within the database. Typically, this refers to edge-match problems observed between the ONC source maps and steps taken to alleviate those problems. A unique line identification number and the data layer to which the description refers are also present in the file. The key (relate) item for accessing the data quality coverage information is the data quality line identification number (DQLNSID). This layer was derived from the VMAP0 series produced by the National Geospatial-Intelligence Agency (NGA), formerly known as NIMA (National Imagery and Mapping Agency), an agency of the United States government. VMAP data set products use the "vector product format" (vpf). The term "VMap" is derived from "Vector Smart Map." Digital Chart of the World is a comprehensive 1:1,000,000 scale vector basemap of the world. It consists of cartographic, attribute, and textual data. The primary source for the database is the National Imagery and Mapping Agency's (NIMA) Operational Navigation Chart (ONC) series. This is the largest scale unclassified map series in existence that provides consistent, continuous global coverage of essential basemap features. The coverage is is organized into 10 thematic layers which feature a vast number of files organized into libraries. These libraries, or coverages, are geographicially bounded areas, rather than feature-linked coverages. DCW Layers in the Harvard Geospatial Library are feature-based as we have processed the multiple tiles from the VMAP0 libraries into a series of seamless coverages (e.g. aeronautical features appear in a single layer, "Aeronautical Facilities, Points") which depict a particular feature as it occurs throughout the available geographic coverage areas. Since different geographic areas were mapped by NIMA at different times using various types of feature capture and scanning and digitizing methods and software, multiple map sources of varying dates and multiple processing approaches are represented in each of these HGL layers. We have necessarily generalized the discussion of data source material and process steps in the Data Quality section of this metadata document.
Purpose
The Digital Chart of the World is a general purpose global database designed to support Geographic Information Systems applications. This layer is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production. This layer will provide a basemap for layers related to socio-economic and political anaylsis, statistical enumeration and analysis, or to support graphical overlays and analysis with other spatial data. More advanced user applications may focus on demographics, urban and rural land use planning and related areas including defining boundaries, managing assets and facilities, integrating attribute databases with geographic features, spatial analysis, and presentation output.
Supplemental Information
Entities (features) and Attributes for DCW are fully described in: Department of Defense, 1992, Military Specification Digital Chart of the World (MIL-D-89009): Philadelphia, Department of Defense, Defense Printing Service Detachment Office. The DCW used a product-specific attribute coding system that is composed of TYPE and STATUS designators for area, line, and point features; and LEVEL and SYMBOL designators for text features. The TYPE attribute specifies what the feature is, while the STATUS attribute specifies the current condition of the feature. Some features require both a TYPE and STATUS code to uniquely identify their characteristics. In order to uniquely identify each geographic attribute in the DCW, the TYPE and STATUS attribute code names are preceded by the two letter coverage abbreviation and a two letter abbreviation for the type of graphic primitive present. The DCW Type/Status codes were mapped into the Feature Attribute Coding Catalogue (FACC) coding scheme. A full description of FACC may be found in The DIgital Geographic Information Exchange STandard (DIGEST) Edition 1.2, January 1994. Please consult the DIGEST FACC website for complete coding data. (http://www.digest.org/html/DIGEST_2-1_Part4_AnnexB.pdf)
Temporal Extent
Currentness Reference
publication date
Time Instant
19920701
Bounding Box
West
-180.000000
East
180.000000
North
90.000000
South
-90.000000
ISO Topic Category
boundaries
location
Theme Keyword
Data Quality
Theme Keyword Thesaurus
DIGEST FACC
Theme Keyword
Boundaries
Quality control
Theme Keyword Thesaurus
LCSH
Place Keyword
Northern Hemisphere
Southern Hemisphere
Eastern Hemisphere
Western Hemisphere
Africa
Asia
Australia
Europe
North America
South America
Polar regions
Place Keyword Thesaurus
LCSH
Temporal Keyword
Access Restrictions
None
Use Restrictions
For educational, non-commercial use only. Although this data set has been developed by the NGA no warranty expressed or implied is made by them as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the NGA in the use of this data, or related materials.
Status
Complete
Maintenance and Update Frequency
Biennial
Point of Contact
Contact Organization
National Geospatial-Intelligence Agency
Delivery Point
Office of Corporate Relations
Delivery Point
Public Affairs Division, MS D-54
Delivery Point
4600 Sangamore Road
City
Bethesda
State
MD
Postal Code
20816-5003
Country
USA
Contact Telephone
800-455-0899
Hours of Service
Monday through Friday 9:00 A.M. to 4:00 P.M. EST-USA
Credit
National Imagery and Mapping Agency (now known as National Geospatial-Intelligence Agency).
Native Data Set Environment
Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 9.0.0.535
Data Quality Information
Attribute Accuracy Report
100 percent of attribute codes were reviewed against the source manuscripts. No formal effort was undertaken to develop a quantitative attribute accuracy statement.
Logical Consistency Report
All data were found to be topologically correct. No duplicate features are present. All areas are completely described as depicted on the source manuscripts. No undershoots or overshoots are present. All data were consistently captured using the rules described in the narrative associated with the Data Quality Table and in the various feature table narrative files present at the coverage level within the library. Special automation techniques The DQNET coverage was created by determining the effective boundaries of each ONC source map and key-entering the coordinates into a digital file that were used to generate linefeatures. Feature coincidence DQNET lines are the boundaries of the effective data areas of each ONC source chart. For this reason, they are strongly correlated with seams in the data. These boundaries manifested as edge-matching problems because of varying data densities, and cartographic decision rules. All line and polygon feature classes include instances where portions of DQNET lines are used to maintain connectivity and/or polygon closure for features in other layers. Database design issues The DQNET coverage is the only coverage with a related attribute table. These were created to maintain one-to-many relations between feature primitives and some of their attributes.
Completeness Report
100 percent of features depicted on the ONC source materials have been captured. 100 percent of the features have valid attribute codes assigned to them. Airport features were derived from the DMA Digital Aeronautical Flight Information File (DAFIF). Where DAFIF was incomplete, locations were added from the ONC.
Horizontal Positional Accuracy Report
The Horizontal Positional Accuracy Value represents overall accuracy. Source chart-specific accuracies are available as area feature attributes in the VMap-0 data quality coverage. The primary accuracy analysis was performed on one chart only in the prototyping phase of the DCW project. Horizontal Positional Accuracy is expressed in meters. Detailed horizontal accuracy figures were developed by comparing the positions of well-defined points in the roads, railroads, utility lines, and drainage coverages against sources of higher accuracy, measuring the offsets, and expressing differences as a Circular Map Accuracy figure at a 90% confidence interval. This figure was independently verified by adding known production errors to source chart accuracies in a root sum square calculation.
Quantitative Horizontal Positional Accuracy Assessment
Lineage
Source
Originator
National Imagery and Mapping Agency
Publication Date
1974-1992
Title
Operational Navigational Chart (ONC)
Geospatial Data Presentation Form
map
Publication Information
Source Scale Denominator
1000000
Type of Source Media
stable-base material
Source Temporal Extent
Time Period Information
Range of Dates/Times
Beginning Date
1974
Ending Date
1992
Source Currentness Reference
ground condition
Contribution
All information found on the source with the exception of aeronautical data. The U.S. Defense Mapping Agency Operational Navigation Chart (ONC) series and the Jet Navigation Charts (JNCs) for the region of Antarctica were the primary sources for the Digital Chart of the World database. The ONCs have a scale of 1:1,000,000, and they are the largest scale, unclassified map series produced by the DMA that provides consistent, continuous global coverage of essential basemap features. Some collateral sources have been used to enhance road and railroad connectivity through selected urbanized areas. The DMA's Digital Aeronautical Flight Information File (DAFIF) was the primary source for the airport data in the aeronautical layer. An Advanced Very High Resolution Radiometer (AVHRR) image for the coterminous United States is the source for the data in the Vegetation layer. The Defense Intelligence Agency Manual (DIAM) 65-18 is the source for the Geopolitical codes and the ocean boundaries information contained in the Political and Oceans layer. The product specifications for the ONCs and JNCs have been used extensively in the design of the database.
Source
Originator
National Imagery and Mapping Agency
Publication Date
199006
Title
Digital Aeronautical Flight Information File
Publication Information
Type of Source Media
magnetic tape
Source Temporal Extent
Time Period Information
Single Date/Time
Calendar Date
1990
Source Currentness Reference
publication date
Contribution
Airport records (name, International Civil Aviation Organization, position, elevation, and type)
Source
Originator
Defense Mapping Agency
Publication Date
1990
Title
Jet Navigational Chart
Geospatial Data Presentation Form
map
Publication Information
Source Scale Denominator
2000000
Type of Source Media
stable-base material
Source Temporal Extent
Time Period Information
Range of Dates/Times
Beginning Date
1974
Ending Date
1991
Source Currentness Reference
publication date
Contribution
All information found on the source with the exception of aeronautical data. JNCs were used as source for the Antartica region only.
Source
Originator
USGS EROS Data Center
Title
Advance Very High Resolution Radiometer
Geospatial Data Presentation Form
remote-sensing image
Publication Information
Source Scale Denominator
1000000
Type of Source Media
magnetic tape
Source Temporal Extent
Time Period Information
Range of Dates/Times
Beginning Date
199003
Ending Date
199011
Source Currentness Reference
publication date
Contribution
6 vegetation types covering the continental US and Canada
Spatial Data Organization Information
Direct Spatial Reference Method
Vector
Point and Vector Object Information
SDTS Terms Description
SDTS Point and Vector Object Type
String
Point and Vector Object Count
13310
Spatial Reference Information
Horizontal Coordinate System Definition
Geographic
Latitude Resolution
0.000001
Longitude Resolution
0.000001
Geographic Coordinate Units
Decimal degrees
Geodetic Model
Horizontal Datum Name
D_WGS_1984
Ellipsoid Name
WGS_1984
Semi-major Axis
6378137.000000
Denominator of Flattening Ratio
298.257224
Vertical Coordinate System Definition
Altitude System Definition
Altitude Datum Name
Mean Sea Level
Altitude Resolution
1.000000
Altitude Distance Units
1.0
Altitude Encoding Method
Explicit elevation coordinate included with horizontal coordinates
Entity and Attribute Information
Entity Type
Entity Type Label
DCW Data Quality Lines
Entity Type Definition
Lines represent data quality features with associated attributes
Entity Type Definition Source
HGL
Attributes
FNODE
Internal node number for the beginning of an arc (from-node). (Whole numbers that are automatically generated.)
Definition Source
ESRI
TNODE
Internal node number for the end of an arc (to-node). (Whole numbers that are automatically generated.)
Definition Source
ESRI
LPOLY
Internal node number for the left polygon (Whole numbers that are automatically generated.)
Definition Source
ESRI
RPOLY
Internal node number for the right polygon. (Whole numbers that are automatically generated.)
Definition Source
ESRI
DQ_
Internal feature number. (Sequential unique whole numbers that are automatically generated.)
Definition Source
ESRI
DQ_ID
User-defined feature number.
Definition Source
ESRI
LFT_ID
Feature Identifer
Definition Source
ESRI
DQLNID
Unique line identifier for those arcs that comprise the ONC module boundaries. This line identifier is used as a key into the Data Quality line relate attribute table (DQLINE.RAT). This relate table contains text information describing specific conditions occurring along this module boundary. Typically this refers to edgematch problems observed on the source maps and steps taken to alleviate the problem.
Definition Source
ESRI
DQLNONC1
ONC sheet numbers on either side of the commented ONC module boundary line.
Definition Source
ESRI
DQLNONC2
ONC sheet numbers on either side of the commented ONC module boundary line
Definition Source
ESRI
TILE_ID
VPF format tile identifier
Definition Source
NIMA
EDG_ID
Primitive Record Identifier for the Feature
Definition Source
NIMA Assigned
SHAPE
Feature geometry. (Coordinates defining the features.)
Definition Source
ESRI
SHAPE.LEN
Polyline length measured in map units
Definition Source
Computed
SHAPE.FID
Internal feature number. (Sequential unique whole numbers that are automatically generated.)
Definition Source
ESRI
Distribution Information
Format Name
Shapefile
Distributor
Harvard Geospatial Library
Name
Metadata Reference Information
Metadata Date
20041112
Metadata Contact
Contact Information
Contact Organization Primary
Contact Organization
Harvard Geospatial Library
Contact Person
Geospatial Resources Cataloger
Contact Address
Address
Harvard University Library
Address
Office For Information Systems
Address
1280 Massachusetts Avenue
City
Cambridge
State or Province
MA
Postal Code
02138
Country
USA
Contact Voice Telephone
617-495-2417
Contact Facsimile Telephone
617-496-0440
Contact Electronic Mail Address
hgl_ref@hulmail.harvard.edu
Hours of Service
Monday - Friday, 9:00 am - 4:00 pm EST-USA
Metadata Standard Name
FGDC Content Standards for Digital Geospatial Metadata
Metadata Standard Version
FGDC-STD-001-1998
Metadata Extensions
Online Linkage
http://www.esri.com/metadata/esriprof80.html
Profile Name
ESRI Metadata Profile
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