DIGITAL CHART OF THE WORLD (DCW) DATA DESCRIPTION
TABLE OF CONTENTS:
1.What is The Digital Chart of the World? 2.How the data set was changed
3.Arc/INFO users 5.ArcView users 6.Known errors and fixes 7.Contact us
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What is the Digital Chart of the World?
The Digital Chart of the World (DCW) is an Environmental Systems Research
Institute, Inc. (ESRI) product originally developed for the US Defense Mapping
Agency (DMA) using DMA data. The DCW 1993 version at 1:1,000,000 scale was used.
The DMA data sources are aeronautical charts, which emphasize landmarks
important from flying altitudes. This explains why there is a separate
aeronautical theme with all conceivable airports, yet why on some themes small
islands and lakes are simply unnamed points. ESRI, in compiling the DCW, also
eliminated some detail and made some assumptions for handling tiny polygons and
edgematching. Also, note that the completeness of the thematic categories
present in each layer will vary. Please read the layer descriptions (through
links in the following table).
Available Themes: Type: Coverage Name Political/Ocean Network PONET Populated
Places Polygon PPPOLY Populated Places Point PPPOINT Railroads Line RRLINE Roads
Line RDLINE Utilities Line UTLINE Drainage Network DNNET Drainage Point DNPOINT
Drainage Supplemental Point DSPOINT Hypsography Network HYNET Hypsography Line
HYPOINT Hypsography SupplementalLine HSLINE Hypsography SupplementalPoint
HSPOINT Land Cover Polygon LCPOLY Land Cover Point LCPOINT Ocean Features Point
OFPOINT Ocean Features Line OFLINE Physiography Line PHLINE Aeronautical Point
AEPOINT Cultural Landmarks Polygon CLPOLY Cultural Landmarks Point CLPOINT
Cultural Landmarks Line CLLINE Transportation StructureLine TSLINE
Transportation StructurePoint TDPOINT Vegetation Polygon VGPOLY
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How the data set was changed
The original format of the DCW from ESRI has 2094 separate Arc/INFO workspaces.
Each workspace is bounded by latitude and longitude, 5-by-5 degrees. Each can
contain up to 25 different thematic layers (see list below). The original
workspaces was compiled into countries, territories and states; our server
contains about 340 of these areas, from the original 2094 workspaces. The parts
of the tiles were aggregated one country at a time, and used each
country-boundary coverage as a "cookie cutter" to select the thematic data
according to country boundaries.
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For Arc/INFO users
Every line coverage needs to be cleaned and every point coverage needs to be
built. For line coverages use the Arc command CLEAN, and for point coverages use
the Arc command BUILD.
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ArcView users
According to the ArcView online help, coverages with more than 5000 arcs can not
be imported into ArcView2 (Windows 3.x) using its import program. The following
export (.e00) files contain more than 5000 arcs, thus ArcView2 cannot import
them as a theme. Therefore, Arc/INFO's IMPORT function must be used to create
the coverage. You can then open the new coverage as a theme in ArcView.
It may be possible to use the ArcView3 import function for NT or UNIX machines.
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Known errors and fixes
The PONET layer for the following areas may have lost some items in the .pat
file, and may not include an .aat file at all. This is because of an error using
the Arc/INFO DISSOLVE command. The ponet layers is a network coverage, thus is
has an .aat and a .pat info file. While compiling these areas the dissolve
command may have deleted the .aat and deleted all the items in the .pat except
the dissolve item.
Antarctica Australia
South Australia Brazil Greenland Mali Mexico Canada China Turkey United States
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Coverages with manual ArcEdit changes to close boundary polygons:
Area Layer China PONET Alaska PONET Brazil PONET Greenland PONET United
StatesPONET Turkey PONET Australia PONET Mexico PONET added UNKNOWN in popyadmin
item Mali PONET
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Redefined items (template coverage used in the Arc APPEND command)
TileLayer Area Date Fixed gg32rdline Panama and Colombia 1/28/97 mj31tsline
Morocco 2/3/97 mj32dnnet France 2/22/97 gg21rdline Ecuador 1/28/97 hg12rdline
Colombia 1/28/97 nm31? Svalbard 1/15/97 pm11? Svalbard 1/15/97 pm21? Svalbard
1/15/97 pm31? Svalbard 1/15/97
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Miscode Errors
The original ESRI tile PG31, item popycoun is miscoded, thus some national
boundaries were wrong. The affected areas were: Uganda, Central African
Republic, Zaire, and the Sudan. Our data was fixed on 1/23/97.
The original ESRI tiles XH32, XH31, XG33, XG23, and YG12 PONET coverages
popycoun item was recoded on 1/13/97. The affected areas were: Federated States
of Micronesia, Guam, and the Northern Mariana Islands.
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Compile Errors
Other errors in the original DCW tiles were found when our AML script tried to
compile the layers in the following list. 0ur data was corrected using the Arc
command CLEAN, in 1/97:
TileLayer Area Error Message FATAL ERROR pj21lcpoly Greece Mismatch of border
segments (NODPOL) Bailing out of BUILD FATAL ERROR pj21lcpoly Egypt Mismatch of
border segments (NODPOL) Bailing out of BUILD FATAL ERROR th33hynet Bhutan Bad
polygon topology (ARCPAL_new) Bailing out of BUILD FATAL ERROR th33hynet India
Bad polygon topology (ARCPAL_new) Bailing out of BUILD FATAL ERROR rj11hynet
Kuwait Bad polygon topology (ARCPAL_new) Bailing out of BUILD FATAL ERROR
vh22hynet Macau Bad polygon topology (ARCPAL_new) Bailing out of BUILD FATAL
ERROR th33hynet Nepal Mismatch of border segments (NODPOL) Bailing out of BUILD
FATAL ERROR ????hynet Hong Kong Bad polygon topology (ARCPAL_new) Bailing out of
BUILD
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Data Sources
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 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.
The 1:1,000,000-scale ONCs were designed to meet the needs of the pilots and air
crews in medium- and low-altitude en route navigation by visual and other
techniques. The ONC series was also designed to support military operational
planning, intelligence briefings, preparation of visual cockpit displays, and
other DMA uses. It is necessary to be mindful of the original purpose of the
source of data when evaluating the suitability of this database for your own
applications.
Operational Navigation Chart (ONC) Product Specification are designed and
produced to support medium altitude en route navigation by dead reckoning,
visual pilotage, celestial, radar, and other techniques. These charts are also
widely used for mission planning/analysis, intelligence briefings, and the
preparation of visual cockpit navigational display/navigational filmstrips. They
provide a small scale (little detail) translation of the cultural and terrain
features for the pilots/navigators flying at medium (2,000 feet to 25,000 feet
AGL) and low altitudes (500 feet to 2,000 feet AGL).
(excerpted from the Digital Chart of the World Data Dictionary)
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Edgematching and Line Connectivity/Polygon Closure
Edgematching of production modules (the nonoverlap areas of the ONCs and JNCs)
was accomplished manually. The basic objective was to establish a
cartographically pleasing match across ONC boundaries whenever possible. The
most accurate and/or current modules were given priority. In poorly mapped areas
of the world, severe feature offsets do occur. In these extreme cases of feature
offset, no edgematching was attempted because the degree of the offset made the
differences irreconcilable. Significant feature offsets also occur in the
instances where the source materials used to compile the ONCs could not be
reconciled. These type of situations may be located anywhere in a tile.
Some Digital Chart of the World layers are developed from ONC separates that do
not contain the necessary connectivity or closure for the linear and polygonal
features represented. For example, road segments are broken on the separates for
the text and urbanized area polygons. These breaks in connectivity were usually
resolved at the map preparation stage.
(excerpted from the Digital Chart of the World Data Dictionary)
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Layer Descriptions
Political and Oceans layer
Coverage name: PONET Feature class type: Polygon Items, codes, and values
POPYTYPE Political/Oceans polygon type
Code Definition
1. = Land 2. = Open Ocean 3. = Polar ice (on water)* 4. = Pack ice (on water)*
5. = Shelf ice*
* Ice on land is contained in the DNNET coverage. These phenomena occur only on
Antarctica, where extensive portions of the land/ocean shoreline is covered by
ice.
Coverage name: PONET Feature class type: Line Items, codes, and values
POLNTYPE Political/Oceans line type
Code Definition
1. = International boundary, de jure 2. = International boundary, de facto 3. =
International boundary, de jure and de facto 4. = Subnational administrative
boundary, first order 5. = Subnational administrative boundary, second order 6.
= Treaty or occupational line (demilitarized zones) 7. = Coastal closure line
(used to connect ocean shoreline across river mouths, glaciers, lagoons, fjords,
and so forth) 8. = Ocean demarcation line (used to separate ocean aggregations)
9. = Ice line (used to separate types of sea ice) 10. = Coastline 11. =
Ocean/Sea ice boundary 12. = Seawall 13. = International date line
88. = Arbitrary connector (if needed)
99. = None (used for tile border)
POLNSTAT Political ocean line status
Code Definition
1. = Definite (boundary or coastline) 2. = Approximate (boundary) or fluctuating
(coastline) 3. = Indefinite (boundary or unsurveyed (coastline) 4. = Man-made
(coastline) (dike) 5. = Indeterminable (coastline) 6. = Ice cliff (when
coincident with the coastline or ice line) 7. = Political boundary (that is,
based on single-line river or stream location) 8. = Connector (international or
administrative boundary extensions through inland water areas) 9. = 5- degree by
5-degree tile boundary
88. = ONC module boundary section retained to provide "edgematch" connection
across ONC sheets
Populated Place layer
Coverage name: PPPOLY Feature class type: Polygon Items, codes, and values
PPPYTYPE Populated place polygon type. This coverage contains depictions of the
urbanized areas (built-up areas) of the world that can be represented as
polygons at 1:1,000,000 scale. The built-up areas represent the shape of an
urbanized area as viewed by the air observer. These outlines do not necessarily
conform to political boundaries.
Code Definition
1. = Urbanized area 2. = Kampong (small villages or groups of houses, especially
in Southeast Asia)
10. = None (non-urbanized area within urbanized area)
Coverage name: PPPOINT Feature class type: Point Items, codes, and values
PPPTTYPE Populated place point type.
Code Definition
1. = Populated place (no subcategories*) 2. = Populated place (associated with
place names within urbanized areas) 3. = Village, strategic, or landmark place
associated with a special symbol identified with an ONC marginal note 4. =
Kampong (small villages or groups of houses, especially in Southeast Asia) 5. =
Circular Village
* On ONCs there are different symbols and text sizes for differentiating the
size or relative importance of populated places. The rank value associated with
these symbols varies from sheet to sheet; for that reason, no attempt was made
to code for the different populated place symbols in the database.
PPPTNAME Place name. The item PPPTNAME contains a thirty-character field to
carry the specific name of the populated feature as it appears on the ONC. Names
are contained in this item.
Railroad layer
Coverage name: RRLINE Feature class type: Line Items, codes, and values
RRLNTYPE Railroad line type.
Code Definition
1. = Single track railroad 2. = Multiple track railroad 3. = Light-duty
railroad, including carlines, tramways, and other similar light-load-bearing
railways
8. = Added railroad connector within urbanized area polygons
RRLNSTAT Railroad line status
Code Definition
1. = Functioning 2. = Nonoperating, abandoned, destroyed, or under construction
3. = Existence doubtful or "reported" to exist 4. = Compiled railroads (used for
arcs added from other source materials in order to provide cartographically
correct connectivity within the urbanized area polygons) 5. = Compiled from
adjacent more recent map sheet (used for arcs added for edgematch or
connectivity in the ONC sheet overlap areas) 6. = Compiled, under construction
(used for arcs added for edgematch or connectivity in the ONC sheet overlap
areas)
8. = Schematic rail line (used for arcs added within the urbanized area polygons
for network connectivity only)
Road layer
Coverage name: RDLINE Feature class type: Line Items, codes, and values
RDLNTYPE Road line type
Code Definition
1. = Dual lane (divided) highway 2. = Primary and secondary road 3. = Track,
trail, or footpath
8. = Added road connector within urbanized area polygons
RDLNSTAT Road line status
Code Definition
1. = Functioning 2. = Under construction 3. = Existence doubtful or "reported"
to exist 4. = Compile road connector (used for arcs added from other source
materials in order to provide cartographically correct connectivity within
urbanized area polygons) 5. = Compiled from adjacent, more recent sheet (used
for arcs added for edgematch or network connectivity in the ONC sheet overlap
areas) 6. = Compiled, under construction (used for arcs added for edgematch or
network connectivity in the ONC sheet overlap areas)
9. = Schematic road (used for arcs added within the urbanized area polygons for
network connectivity only)
Utilities layer
Coverage name: UTLINE Feature class type: Line Items, codes, and values
UTLNTYPE Utility line type
Code Definition
1. = Power transmission line 2. = Telephone or telegraph line 3. = Above-ground
pipeline 4. = Underground pipeline
Drainage layer
Coverage name: DNNET Feature class type: Polygon Items, codes, and values
DNPYTYPE Drainage feature type
Code Definition
1. = Perennial inland water. Includes perennial lakes and streams, estuaries,
lagoons, unsurveyed perennial streams, reservoirs, and navigable canals 2. =
Nonperennial inland water. Includes nonperennial and seasonally fluctuating
lakes and streams, wadis, sabkhas, and abandoned navigable canals 3. = Wet sand.
Includes wet sand and sand deposits in and along riverbeds 4. = Snowfields,
glacier, ice fields, or ice caps
9. = None. This code is used for any area that is not water, wet sand,
snowfield, glacier, ice field or ice cap. Polygons with this code would include
the background polygon, islands within inland water or ice areas, land areas
enclosed by stream or river courses, or ocean areas.
Coverage name: DNNET Feature class type: Line Items, codes, and values
DNLNTYPE Drainage line type
Code Definition
1. = Stream, river, channelized river 2. = Inland water body shoreline 3. = Wet
sand limit 4. = Canal, aqueduct, flume, penstock, kanat, or similar feature
(clearly identified by ONC map annotation) 5. = Glacial limit 6. = Snowfield,
glacier, or land ice water ice or ocean limit 7. = Ice free limit (land/ice
line) 8. = Connector (used to separate inland water from open ocean or ocean
ice)* 9. = Tile boundary or null arc
*These lines were derived from the border between the shade for inland water
(dark blue) and open ocean or ocean ice (light blue) on the ONC sheets. The
cartographic judgements applied to the use of open ocean versus inland water
shading in near shore situations varies from sheet to sheet,
DLNSTAT Drainage line status.
Code Definition
1. = Perennial (used for rivers and streams only) 2. = Nonperennial (used for
rivers and streams only) 3. = Definite (used for inland shorelines only) 4. =
Indefinite (used for inland shorelines only) 5. = Unsurveyed perennial 6. =
Unsurveyed nonperennial 7. = Abandoned 8. = Under construction 9. = Suspended or
elevated 10. = Underground 11. = Above ground
88. = Tile boundary
99. = None (no status attribute associated with feature)
Coverage name: DNPOINT Feature class type: Point Items, codes, and values
DNPTTYPE Drainage point type.
Code Definition
1. = Spring, well, waterhole, or bore 2. = Small reservoir 3. = Falls 4. =
Rapids 5. = Lock 6. = Dam* 7. = Sluice gate
*Those dams shown on the ONCs with their true shape and extent are also present
as line data in the Cultural Landmark layer.
Supplemental Drainage Layer
Coverage name: DSPOINT Feature class type: Point Items, codes, and values
DSPTTYPE Supplemental drainage point type. This item contains those ONC drainage
features which could not be captured as polygons during the scanning process.
Polygons less than 0.12 inches in circumference were automated as point
features. The resulting point location is located on the perimeter of the former
polygon feature.
Code Definition
1. = Small lake, inland water body (lakes, reservoirs, lagoons) 2. = Small
island within inland water areas
Hypsography layer
Coverage name: HYNET Feature class type: Polygon Items, codes, and values
HYPYTYPE Hypsography polygon type. The hypsography polygons are coded to form
elevation zones, as indicated in the classification scheme below.
Code Definition
1. = Below mean sea level 2. = 0 to 1,000 feet above mean sea level 3. = 1,000
to 3,000 feet 4. = 3,000 to 7,000 feet 5. = 7,000 to 11,000 feet 6. = 11,000
feet and above 7. = Uncontoured or unsurveyed 8. = Area does not have a
1,000-foot contour interval (only exists on JNC) 9. = None
Coverage name: HYNET Feature class type: Line Items, codes, and values
HYLNVAL Hypsography line value. The item HYLNVAL contains the elevation value of
the contour line expressed as feet above mean sea level. When contour lines for
different elevations become coincident, as in areas of steep local relief, only
a single carrying contour is shown and is coded for the value for the highest
elevation present. Valid contour line codes range from -1,000 feet to 29,000
feet incrementing by 1,000 feet. Boundaries associated with no data areas are
assigned a value of 99999.
HYLNTUYPE Line Type.
Code Definition
1. = Closed contour. 2. = Depression contour. 3. = Closed contour, approximate.
4. = Carrying contour, coalescence of two or more contour lines with different
elevation values 5. = Depression contour, approximate
8. = Connector (an arbitrary connector of the contour network, used to define no
data or irreconcible source data areas. These connections were made to establish
elevation zones as polygons.) 9. = 5-degree by 5-degree tile boundary.
88. = Used in situations during the edgematching process in which a polygon is
contained on one ONC mapping module due to compilation differencies and the
automation module boundary is needed for closure.
Coverage name: HYPOINT Feature class type: Point Items, codes, and values
HYPTTYPE Hypsography point type
Code Definition
1. = Spot elevation 2. = Spot elevation, questionable or doubtful location 3. =
Spot elevation at the base of a tower 4. = Hydrographic spot elevation
HYPTVAL Point value. This item contains the elevation of the point, expressed in
feet above the mean sea level. The value "99999" is used for spot locations
without an assigned elevation value.
Hypsography Supplemental layer
Coverage name: HSLINE Feature class type: Line Items, codes, and values
HSLNTYPE Supplemental hypsography line type. This item indicates the specific
type of the supplemental contour line. This coverage contains unclosed contours
and/or contours at intervals other than 1,000 feet.
Code Definition
1. = Intermediate or auxiliary contour* 2. = Depression contour 3. = Approximate
intermediate or approximate auxiliary contour* 4. = Carrying contour,
coalescence of two o more contour lines with different elevation values 5. = Cut
within one contour interval, and fill within one contour interval 6. =
Unreliable (present in Antarctic tiles only) 7. = Transition or erroneous
contour 8. = Approximate depression contour
* An intermediate contour is one that is required between basic contours to
portray form, degree of slope, and elevation not shown by the basic contour
interval. An auxiliary contour is one that is used to portray configuration and
relative relief significance of additional land forms not adequately portrayed
by basic and/or intermediate contours.
HSLNVAL Supplemental hypsography line value. The item HSLNVAL contains the
elevation value of the contour line in feet above mean sea level (MSL). The code
99999 is used when an elevation value is not applicable.
Land Cover Layer
Coverage name: LCPOLY Feature class type: Polygon
Items, codes, and values
LCPYTYPE Land cover polygon type.
Agricultural/Extraction Features Code Definition
1. = Rice field 2. = Cranberry bog 3. = Cultivated area, garden 4. = Peat
cuttings 5. = Salt pan 6. = Fish pond/ hatchery 7. = Quarry, strip mine, mine
dump, and blasting area 8. = Oil/Gas
Surface Cover Features Code Definition
10. = Lava flow 11. = Distorted surface area 12. = Unconsolidated material 13. =
Natural landmark area 14. = Inundated area 15. = Undifferentiated wetlands
Coverage name: LCPOINT Feature class type: Point
LCPTTYPE Land cover point type
Code Definition
1. = Mine 2. = Quarry, strip mine, mine dump, and blasting area 3. =
Miscellaneous land feature (e.g., mountain name, cave, sink hole, basalt
pinnacle)
Ocean Features layer
Coverage name: OFLINE Feature class type: Line Items, codes, and values
OFLNTYPE Ocean features line type
Code Definition
1. = Miscellaneous ocean feature 2. = Reef 3. = Maritime area limit
Coverage name: OFPPOINT Feature class type: Point Items, codes, and values
OFPTTYPE Ocean features point type
Code Definition
1. = Rocks, isolated or awash 2. = Exposed wreck
Physiography layer
Coverage name: PHLINE Feature class type: Line Items, codes, and values
PHLNTYPE Physiography line type
Code Definition
1. = Levee, dike, or esker 2. = Rock strata outcrop 3. = Escarpment, bluff,
cliff, etc. 4. = Earthquake fault 5. = Ice cliff on land 6. = Crater
Aeronautical layer
Coverage name: AEPOINT Feature class type: Point Items, codes, and values
AEPTTYPE Aeronautical point type. Airport feature in Codes 1 through 4 were
derived from the DMA Digital Aeronautical Flight Information File (DAFIF). Where
this file was incomplete, data were added from the ONCs (primarily in Eastern
Europe and the former Soviet Union).
Code Definition
1. = Active civil 2. = Active civil and military 3. = Active military 4. = Other
5. = Airport location added from ONC source when not available in the DAFIF
Cultural Landmark layer
Coverage name: CLPOLY Feature class type: Polygon Items, codes, and values
CLPYLABEL Cultural landmark polygon type. The type of landmark is entered in
this text field. Representative values are fort, racetrack, athletic field, area
delimiting line (label), and structure other than building (label)
Coverage name: CLPOINT Feature class type: Point Items, codes and values
CLPTLABEL Cultural landmark point label. Labels are entered for the symbols, if
any, with labels. About 150 representative values are listed in the Digital
Chart of the World Data Dictionary. Examples are: ancient ruins, cemetery, gas
well, mountain pass, military area, power plant, racecourse.
Coverage name: CLLINE Feature class type: Line Items, codes, and values
CLLNLABEL Cultural landmark line label. Representative values include Wier,
jetty, and groyne Boat ramp Pier, wharf, quay Breakwater Aerial cableway Wall,
trench, tank trap Prominent fence Dams*
*The dams in this layer are those shown on the ONC with their true shape and
extent. Those dams that are represented only by a graphic symbol are present as
point data in the Drainage layer. All dams in the CLLINE coverage are also
represented as points in DNPOINT coverage. These features are not always
coincident with inland water shorelines (DNNET).
Transportation Structure layer
Coverage name: TSLINE Feature class type: Line Items, codes, and values
TSLNTYPE Transportation structure line type.
Code Definition
1. = Road structure 2. = Railroad structure
TSLNSTAT Line status.
Code Definition
1. = Snowshed 2. = Bridge 3. = Causeway 4. = Tunnel 5. = Ferry 6. = Ford
Coverage name: TSPOINT Feature class type: Point Items, codes, and values
TSPTTYPE Transportation point type.
Code Definition
1. = Road structure 2. = Railroad structure
Point status.
Code Definition
1. = Snowshed 2. = Bridge 3. = Causeway 4. = Tunnel 5. = Ferry 6. = Ford 7. =
Railroad yard 8. = Railroad station
Vegetation layer
Coverage name: VGPOLY Feature class type: Polygon Items, codes, and values
VGPYTYPE Vegetation polygon type. This layer contains land coverage information
for the coterminous United States only. The vegetation information from the ONC
source materials was omitted from the database because it was so restricted to
air crews' requirements as to be of little general use. A classified Advanced
Very High Resolution Radiometer (AVHRR) image was vectorized to provide a sample
set of vegetation data. The attribute codes used here correspond with the USGS?s
Level II codes in the Land Use and Land Cover Classification System for Use with
Remote Sensor Data (Anderson, Hardy, Roach, and Witmer, USGS Professional Paper
964, 1976).