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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 ------------------------------------------------------------------------ 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 ------------------------------------------------------------------------ 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. ------------------------------------------------------------------------ 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. ------------------------------------------------------------------------ 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. ------------------------------------------------------------------------ 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 ------------------------------------------------------------------------ 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 ------------------------------------------------------------------------ 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 ------------------------------------------------------------------------ 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. ------------------------------------------------------------------------ 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 ------------------------------------------------------------------------ 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) ------------------------------------------------------------------------ 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) ------------------------------------------------------------------------ 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). (excerpted from the Digital Chart of the World Data Dictionary) ------------------------------------------------------------------------