3

EDITORIAL RULES, CONTINUED

3.7

Coordinates

Included in this chapter

• Coordinates
  Latitude:
  Degree; Minute; Second; Direction; Decimal Degrees
  Longitude:
  Degree; Minute; Second; Direction; Decimal Degrees

• Bounding Coordinates
  Least Latitude:
  Degree; Minute; Second; Direction; Decimal Degrees
  Most Latitude:
  Degree; Minute; Second; Direction; Decimal Degrees
  Least Longitude:
  Degree; Minute; Second; Direction; Decimal Degrees
  Most Longitude:
  Degree; Minute; Second; Direction; Decimal Degrees
• Elevation
  Elevation:
  Feet; Meters



• Example
  [for Great Lakes Region in VCS]

[end-user display for Great Lakes Region]

3.7.1

Coordinates

3.7.1.1

Definition
Geographic coordinates indicating the point on the globe where the place is located, expressed in degrees/minutes/seconds and decimal fractions of degrees.

So far as is possible given that TGN is compiled from various contributors, coordinates in TGN are compliant with following standards: ISO 6709 Standard representation of geographic point location by coordinates, using the WGS 84 (revised 2004) coordinate reference system.

Fields

Latitude:
Degree; Minute; Second; Direction
Decimal Degrees

Longitude:

Degree; Minute; Second; Direction
Decimal Degrees

3.7.1.3

Values

• Valid values are controlled by VCS.

• Latitude: Degree: 0 to 90; Minute: 0 to 60; Second: 0 to 60; Direction: N or S (for north or south)

• Longitude: Degree: 0 to 180; Minute: 0 to 60; Second: 0 to 60; Direction: E or W (for east or west)

• Latitude Decimal Degrees: 0 to +/-90 with decimal fractions

• Longitude Decimal Degrees: 0 to +/-180 with decimal fractions

3.7.1.4

Sources

3.7.1.4.1

List of Sources
Sources for coordinates are standard general reference works, in the following order of priority:

• NGA GEOnames query (for places in nations other than the USA) http://earth-info.nga.mil/gns/html/index.html
  
  
• USGS National Mapping Information query form (for places in the USA) http://geonames.usgs.gov/
  
  
• The index of Times Comprehensive Atlas of the World, 13th ed.
  
  
• The index of Oxford Atlas of the World, 20th ed.
  
  
• The index of the National Geographic Atlas of the World, 9th edition
  
  
• The index of Rand McNally New International Atlas, 25th anniversary edition
  
  
• Columbia Gazetteer of the World, 2nd edition
  
  
• Other authoritative hardcopy or online sources.
  
  
• If you consult multiple sources and the coordinates vary from source to source, prefer the most current and authoritative source.

• Caveat: If you use sources other than the ones named above, carefully ascertain that the coordinates listed in the source represent the same type of standard geographic coordinates (also called geographical or terrestrial coordinates) compliant with ISO 6709 and WGS 84 (revised 2004), as preferred in TGN. There are other types of coordinate systems, including various local systems, other national systems, and systems derived by other criteria. How can you tell if the coordinates in your source are compatible with TGN data? Compare the numbers used in the coordinate system of your source with coordinates of other TGN records for places that are near the place you are recording.

• GPS: If you have access to a Global Positioning System (GPS) receiver that has been proven to be accurate and reliable, you may use this as your source of coordinates. The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of between 24 and 32 satellites, compliant with with ISO 6709 and WGS 84 (revised 2004). Originally intended for military applications, the government made the system available for civilian use in the late 1980s and handheld receivers are commercially available today, including as applications on smart phones. A good quality GPS will be able to locate a position to within 40 meters or better. If you use a GPS for coordinates, include the citation Global Positioning System (GPS) receiver (n.d.) in the Subject Source and put the brand, model, and date of the reading in the Page field.
  

3.7.1.5

Discussion

• Standards: TGN endeavors to comply with the ISO 6709 Standard representation of geographic point location by coordinates. ISO 6709 is the international standard for representation of latitude, longitude and altitude for geographic point locations. ISO 6709 provides a means for indicating the coordinate reference system used, which is WGS 84 (revised 2004) in TGN.
  
  TGN endeavors to use WGS 84 coordinate reference system, so far as is possible given that TGN is compiled from various contributors' data. WGS 84 is the reference system used most widely in the world: It is the standard used by the US Department of Defense and used for Global Positioning Systems (GPS). WGS 84 is compatible with the International Terrestrial Reference System (ITRS). WGS 84 is an Earth-centered, Earth-fixed terrestrial reference system and geodetic datum. WGS 84 is based on a consistent set of constants and model parameters that describe the Earth's size, shape, and gravity and geomagnetic fields. It is defined in the US National Geospacial-Intelligence Agency (NGA, formerly NIMA) Technical Report 8350.2. WGS 84 uses the EGM96 (Earth Gravitational Model 1996) geoid, last revised in 2004.
  


• Latitude: Geographic latitude is the angular distance north or south of the equator, measured along a meridian. Parallels of latitude are equidistant circles drawn around the globe parallel to the equator. Measurements along the parallels are traditionally given in degrees, minutes, and seconds (counted in increments of 60, as with a clock), combined with a directional indicator for north (N) or south (S). The equator is at 0 degrees; 90 degrees north is the North Pole, 90 degrees south is the South Pole. The greatest possible latitudes are 90° N and 90° S.

• Longitude: Longitude is the angular distance east or west of the Prime Meridian, which runs through Greenwich, England. Meridians are imaginary north-south lines on the Earth's surface that connect both geographic poles, used to measure longitude. Measurements along the meridians are traditionally given in degrees, minutes, and seconds (counted in increments of 60, as with a clock), combined with a directional indicator for east (E) or west (W). The prime meridian is at 0 degrees; 180 degrees is the International Date Line. The greatest longitude is measured 180° both east and west of the prime meridian.

• Given that meridians are closer together nearer the poles and further apart nearer the equator, any flat projection of the globe as a grid with 45-degree angles on a map is somewhat inaccurate. As an editor, you generally do not need to compensate for this inaccuracy, but you should be aware of it when you consult maps. Maps of the same area may vary in appearance, depending upon what method of projection was used.
  
  
• The combination of meridians of longitude and parallels of latitude establishes a grid by which exact positions can be determined. Coordinates in TGN represent the point on the grid where latitude and longitude cross (e.g., in the illustration below, the point at 40 degrees north and 30 degrees west is illustrated).
  
  
  • Illustration

image from Encyclopedia Britannica Online (2002-) http://www.eb.com/, (accessed 11 August 2004)

• Most of the records in the TGN include geographic coordinates that represent a single point for each place, corresponding to a point at or near the center of the inhabited place, political entity, or physical feature. For linear features such as rivers, the point represents the source of the feature.

• Decimal degrees: Coordinates are expressed in degrees, minutes, and seconds, corresponding to the standard used in atlases and illustrated above. In TGN, coordinates are also expressed in decimal fractions of degrees where minutes and seconds are translated into decimal values, (e.g., 40 degrees 30 minutes 00 seconds = 40.5000 decimal degrees). The expression of coordinates in decimal degrees is used in Geographic Information Systems (GIS) and for other applications where mathematical calculations are necessary. In decimal fractions, the directional indicators (e.g., north, south, east, or west) are not included. Instead, directions are indicated by using sets of positive and negative numbers: north latitude and east longitude are expressed as positive numbers; south latitude and west longitude are expressed as negative numbers (as in the example for Rio de Janeiro below).

3.7.1.6

RULES

3.7.1.6.1

Minimum requirements
Coordinates are not required, but they are strongly recommended.

• It is a higher priority to include coordinates for administrative entities than for physical features (because administrative entities - such as inhabited places - are typically more important for catalogers of art and cultural heritage materials, the intended audience of TGN).

• Enter only valid values, as listed under Values above. Do not use punctuation except with decimal degrees, where a period must be used as the decimal point separating the whole number from fractions of a degree and a hyphen is used for negative numbers.

3.7.1.6.2

Degrees/minutes/seconds vs. Decimal degrees
Atlases and geographic dictionaries, including the sources listed above, will typically record coordinates in degrees/minutes/seconds rather than in decimal degrees. Carefully transcribe the numbers and direction into the appropriate fields in VCS. Allow the system to automatically fill in the decimal value.

• If your source lists decimal values, carefully transcribe them in the Decimal field, including the period for decimal fractions and a hyphen for the negative numbers, as appropriate. Allow the system to automatically fill in degrees/minutes/seconds for you.
  
  
  • Example
    [for Rio de Janeiro, in VCS]

• Caveat: You will not be able to correctly transcribe zeroes as found in your sources into the VCS fields. Due to a technical idiosyncrasy of VCS, it will not save more than one zero in the degree/minute/second fields; it will not save zeroes to the far right of the decimal point in the Decimal field either. Note that publication algorithms compensate for this flaw by adding zeroes in accord with geographic information standards, which require zeroes to fill in the required positions (compare the coordinates for Rio de Janeiro in VCS above and as published, below).
  
  
  • Example
    [for Rio de Janeiro, in an end-user display]

3.7.1.6.3

What do the coordinates represent?
As described in the Discussion above, the coordinates are intended to represent a point at or near the center of a place. For linear features, such as a river, the point should represent the source of the feature.

• Inhabited places and physical features: Record coordinates as found in your source. As an editor, you typically should transcribe coordinates from a published source; do not use a map to estimate coordinates for small places, such as inhabited places or small features, because they will be too inaccurate.

• Regions and large physical features: In some cases, such as for a general region, large physical feature, or other area, you may be required to estimate coordinates for the center of the area because they are not included in your sources. In general, the accuracy of the center of large features is not expected to be as precise as for small entities, therefore it is permitted to estimate coordinates for large areas and features by using a map.
  • Use a large map (e.g., in an atlas); on the map, draw an imaginary line through the vertical center of the area; draw another imaginary line through the horizontal center of the area. Record the coordinates representing the point where the two imaginary lines intersect.
    
    
  • If you use a map as described above, Record zeroes for seconds; if you record very specific numbers, it gives the mistaken impression that you have measured the center by a scientific means (whereas, you are in reality only estimating the center, based on sight).
    
    
    • Example
      [for the Kalahari Desert, Africa]

3.7.1.6.4

Accuracy of the coordinates
Coordinates in the sources named above are approximate and are intended only for finding the place on the map. (Of course, you must be careful to accurately transcribe them, none-the-less.)

• Sensitive sites: It is standard practice to avoid giving accurate coordinates for archaeological sites, caves, other environmentally sensitive sites, or politically sensitive sites. As an editor, you need not be concerned with this, provided you find the coordinates in the standard published sources named above; feel free to record them in TGN. However, if you somehow have access to precise coordinates (e.g., by accessing materials belonging to an archaeological project), do not record these more accurate, unpublished coordinates in TGN.
  

3.7.1.6.5

Citing your source
The coordinates fields are not linked directly to the source table. Therefore, you should cite the source for your coordinates in the Subject Source area, if you have not cited it elsewhere. (If the same source was used for names and/or the descriptive note, and the source is thus cited in these areas, you needn't list it again under Subject Source.)

• Example

• If you used a GPS for coordinates, include the citation Global Positioning System (GPS) receiver (n.d.) in the Subject Source and put the brand, model, and date of the reading in the Page field.

3.7.2

Bounding Coordinates

3.7.2.1

Definition
A set of four lines expressed as geographic coordinates, indicating four sides of a box encompassing a region, feature, or other area.

3.7.2.2

Fields

Least Latitude:
Degree; Minute; Second; Direction
Decimal Degrees

Most Latitude:
Degree; Minute; Second; Direction
Decimal Degrees

Least Longitude:
Degree; Minute; Second; Direction
Decimal Degrees

Most Longitude:
Degree; Minute; Second; Direction
Decimal Degrees

3.7.2.3

Values

• Valid values are controlled by VCS.
  
  
• Least and Most Latitude: Degree: 0 to 90; Minute: 0 to 60; Second: 0 to 60; Direction: N or S (for north or south)
  
  
• Least and Most Longitude: Degree: 0 to 180; Minute: 0 to 60; Second: 0 to 60; Direction: E or W (for east or west)
  
  
• Least and Most Latitude Decimal Degrees: 0 to +/-90 with decimal fractions
  
  
• Least and Most Longitude Decimal Degrees: 0 to +/-180 with decimal fractions
  

3.7.2.4

Sources

3.7.2.4.1

List of Sources

• Estimated coordinates: Most standard sources, such as atlases and geographic dictionaries, do not include bounding coordinates. In most cases, you will need to consult a map and estimate bounding coordinates by sight. Standard atlases with appropriate maps include the following:
  
  
  • Times Comprehensive Atlas of the World, 13th ed.
    
  • Oxford Atlas of the World, 20th ed.
    
  • National Geographic Atlas of the World, 9th ed.
  • Rand McNally New International Atlas, 25th anniversary edition
    
    
• Coordinates from a source: Some sources include bounding coordinates. Use only authoritative sources, such as official Web sites for a national or state government.
  
  
• If you consult multiple sources and the coordinates vary from source to source, prefer the most current and authoritative source.
  

3.7.2.5

Discussion

• Bounding coordinates define the limits of coverage of an area or feature expressed by latitude and longitude values for the western-most, eastern-most, northern-most, and southern-most points (as illustrated below).

• Illustration

• In TGN, bounding coordinates are called Least and Most, referring strictly to the numerical value of the decimal coordinates; obviously, these numbers could be mapped to the cardinal directions as the western-most, eastern-most, northern-most, and southern-most points.

• Bounding coordinates define a quadrilateral, meaning a figure bound by four straight lines. The figure so formed is generally a rectangle, meaning that the lines comprise two parallel pairs, joined at the four points in right angles.

3.7.2.6

RULES

3.7.2.6.1

Minimum requirements
Bounding coordinates are not required. Enter them as editorial priorities allow.

• If you enter bounding coordinates, it is required to also enter Coordinates (representing a point in the center of the area; see 3.7.1 Coordinates above).
  
  
• If you enter one bounding coordinate, you must enter coordinates for all four sides of the bounding box.
  
  
• Enter only valid values, as listed under Values above. Do not use punctuation except in decimal degrees, where a period should be used as the decimal point separating the whole number from fractions of a degree and the hyphen is used for negative numbers.

3.7.2.6.2

When to list bounding coordinates
It is generally more important to list bounding coordinates for a large area or large physical feature that is not well represented by a single set of coordinates (representing one point), than for a smaller place.

• However, bounding coordinates may be recorded for a relatively small area, such as an inhabited place or physical feature, if they are supplied by your source. Do not acquire bounding coordinates by trying to draw an imaginary bounding box for a small area

3.7.2.6.3

Degrees/minutes/seconds vs. Decimal degrees
If your source lists decimal values, carefully transcribe the north-, south-, east-, and west-most extents of the area or feature into the Most and Least fields for latitude and, including decimal fractions and a hyphen for the negative numbers, as appropriate. Allow the system to automatically fill in degrees/minutes/seconds/direction for you.

• If your source lists bounding coordinates in degrees/minutes/seconds, carefully transcribe the numbers and direction into the appropriate fields. Allow the system to automatically fill in the decimal value.

• If you use a map to determine for yourself the four points representing the area or feature, draw an imaginary box around the area or feature (as for the illustration of Lazio/Latium below). Draw the tightest box possible to include the area or feature. Make the lines perpendicular (the corners of the box should be right angles), unless instructed to do differently by your supervisor. For each of the four imaginary lines, enter degrees/minutes/seconds and direction of latitude or longitude in the appropriate Most and Least fields. Allow the system to automatically fill in the decimal value.
  
  
• Most Latitude must be a number greater than Least Latitude; Most Longitude must be a number greater than Least Longitude. As you calculate which fields to use for numbers that are greater and smaller than each other, keep in mind that Most and Least refer to the decimal degrees, which may be negative numbers (north latitude and east longitude are expressed as positive numbers; south latitude and west longitude are expressed as negative numbers).
  
  
  • Example
    [for the region of Lazio (Latium), Italy]

• Illustration

3.7.2.6.4

Accuracy of the coordinates
Bounding coordinates, whether found in sources or determined by the editor examining a map, are generally approximate and are intended only for finding the place on the map.

• If you have estimated the bounding coordinates by sight by consulting a map, record the seconds as zero to avoid the impression that the coordinates are more accurate than they actually are.

3.7.3

Elevation

3.7.3.1

Definition
The vertical distance of the place above or below mean sea level.

3.7.3.2

Fields

• Elevation:
  Feet; Meters

3.7.3.3

Values

• Valid values are controlled by VCS.
  
  
• Elevation Feet: Positive or negative numbers, including decimal fractions.
  
  
• Elevation Meters: Positive or negative numbers, including decimal fractions.

3.7.3.4

Sources

3.7.3.4.1

List of Sources
Geographic dictionaries, encyclopedia articles, and other sources may include elevation in the description of the place. Atlases sometimes include elevation for peaks and ocean floor features on the maps (typically elevation is not listed with the coordinates, which are generally found in the indexes of atlases). The following sources are preferred:

• United States Geological Survey (USGS). Geographic Names Information System (GNIS) [online database]. Washington, DC: U.S. Geological Survey, 1998-. http://geonames.usgs.gov/ (27 February 2014). (only for places in the USA).
• National Geospacial-Intelligence Agency GEOnames (for places in nations other than the USA) http://earth-info.nga.mil/gns/html/index.html (27 February 2014).
• Times Comprehensive Atlas of the World. 13th comprehensive ed. New York: Times Books, 2011.
• Oxford Atlas of the World. 20th ed. New York: Oxford University Press, 2013.
• National Geographic Atlas of the World. Revised 9th ed. Washington: National Geographic Society, 2010.
• New International Atlas. 25th Anniversary Ed. Chicago: Rand McNally, 2008.
• Encyclopaedia Britannica. Britannica Online. Chicago: Encyclopedia Britannica, Inc., 2002-. http://www.britannica.com/ (27 February 2014).
• Merriam-Webster's Geographical Dictionary. 3rd ed. Springfield, MA: Merriam-Webster, 2007.
• Columbia Gazetteer of the World. 2nd ed. New York: Columbia University Press, 2008.
• Journal articles from National Geographic, Archaeology Magazine, or other authoritative journals.
• Official national Web sites or other authoritative online sources.

• If you consult multiple sources and the elevation varies from source to source, prefer the most current and authoritative source.

• GPS: You may use a Global Positioning System (GPS) receiver as a source for elevation if it has a built in altimeter that has been proven accurate. The best GPS receivers can give elevation with accuracy within 3 meters. Record Global Positioning System (GPS) receiver (n.d.) as a Subject Source. Note the brand, model number, and date of the reading in the Page field.

3.7.3.5

Discussion

• In most sources, zero elevation is the height of mean sea level, which is determined by a series of observations at various points along the seashore taken continuously for a given period of years. However, sea level varies from place to place, due to ocean currents, gravity, and other physical forces. Therefore, some sources give geoid elevation, which is the elevation above the surface of the geoid (an imaginary shape for the earth defined by mean sea level and its imagined continuation under the continents at the same level of gravitational potential). Elevation may be determined by traditional surveying or by Global Positioning Satellite (GPS). Elevation for a single place may vary slightly from source to source, depending upon which method was used to measure it and other factors.
  
  
• Elevation in TGN is intended to be approximate; therefore, enter elevation in the Elevation field regardless of which of the above methods is used by your source.
  

3.7.3.6

RULES

3.7.3.6.1

Minimum Requirements

• Elevation is not required. Enter elevation as editorial priorities allow.
  
  
• If you enter elevation, it is strongly recommended to enter coordinates (see 3.7.1 Coordinates above), if possible. It is a higher priority to record coordinates than to record elevation.
  
  
Use only the valid numbers, as listed under Values above. Do not use commas or any other punctuation except for the period, which may be used as the decimal point separating the whole number from fractions of a foot or meter, and the hyphen, which is used for negative numbers (that is, for distances below sea level).
• Example
  [for the Himalayas mountain system]

.

3.7.3.6.2

How to record elevation
If your source lists elevation in feet, carefully transcribe the feet, including a hyphen for negative numbers (i.e., below sea level). Feet are generally rounded off; however, if your source lists a decimal fraction for feet, include it. Allow the system to automatically fill in the meters value.

• If your source lists elevation in meters, carefully transcribe the value, including decimal fractions and a hyphen for negative numbers (i.e., below sea level). Allow the system to automatically fill in the feet for you.
  
  
• If your source lists a range of elevation, as for a mountain range, record the highest elevation.

3.7.3.6.3

Citing your source
The elevation field is not linked directly to the source table. Therefore, you should cite the source for elevation in the Subject Source area, if you have not cited it elsewhere. (If the same source was used for names and/or the descriptive note, and the source is thus cited in these areas, you needn't list it again under Subject Source.)

Last updated 27 February 2014
Document is subject to frequent revisions