Database Fields: Definitions and Specifics

Coordinates listed in columns labeled "lat" and "long" are taken from the maps identified in columns "quad" and "map," or from digital images. Note that coordinates of features are updated from time to time as new control networks and image mosaics become available. For maps published by the USGS the field "quad" identifies the informal name of the map, and the field "map" lists the USGS map identification ("I" or "SIM") number. In identifying lunar maps published by the DMA or ACIC in the 1960s and early 1970s or Soviet maps of Venus published in 1985 and 1986, we use different systems of identification, as shown in the key below.

We identify the continent ("CT") and ethnic/cultural group or country ("ET") of a name in order to compute and equalize international representation (see Abbreviations for Continents, Countries, and Ethnic Groups).

Names shown in gray type and in brackets are not currently in use. These names have either been dropped or were never officially approved. Dropped names have an approval status of 6, and names that were never officially approved have an approval status of 7.


Column Classification and Codes

Label Description
Target Planet or Satellite where the name is found.
Feature Name As spelled by honoree or by reference shown in References; brackets indicate that the name has been dropped or was never officially approved. This field shows the names with the diacritical marks.
Clean Feature Name This field shows the feature name without the diacritical marks which can cause display issues in some programs. The correct spelling of a feature name includes diacritical marks not shown in this field.
Center Latitude Latitude of center of feature. Positive numbers indicate that the feature is located in the northern hemisphere, and negative numbers indicate that the feature is located in the southern hemisphere.
Center Longitude Longitude of center of feature. Degrees 0 to 360 in an east or west system. On the Moon, positive longitude values indicate east longitudes, and negative values indicate west longitudes.
Northern Latitude Northernmost latitude of feature. Positive numbers indicate that the feature is located in the northern hemisphere, and negative numbers indicate that the feature is located in the southern hemisphere.
Southern Latitude Southernmost latitude of feature. Positive numbers indicate that the feature is located in the northern hemisphere, and negative numbers indicate that the feature is located in the southern hemisphere.
Eastern Longitude Easternmost longitude of feature. Degrees 0 to 360 in an east or west system. On the Moon, positive longitude values indicate east longitudes, and negative values indicate west longitudes.
Western Longitude Westernmost longitude of feature. Degrees 0 to 360 in an east or west system. On the Moon, positive longitude values indicate east longitudes, and negative values indicate west longitudes.
Diameter Approximate diameter or longest dimension of feature in kilometers.
CT (Continent) Continent or large geographic division that is origin of name (see Abbreviations for Continents, Countries, and Ethnic Groups).
ET (ethnic/cultural group or country) Country or ethnic group that is origin of name (see Abbreviations for Continents, Countries, and Ethnic Groups).
Approval Status
Number indicates IAU level of approval:
Code Approval Level
1 Adopted by IAU
2 Dropped, no longer in use
3 Never approved by the IAU
Approval Date Date when name was adopted. Starting in mid-September 2006, complete dates are recorded (YYYY-MM-DD). Before mid-September 2006, only the approval year was recorded.
Coordinate System The Coordinate System used for the Latitude and Longitude values.
Reference Reference from which spelling and origin information were derived (see References).
Feature Type Latin or Greek descriptor term (see Descriptor Terms (Feature Types)).
Quad The specific planetary quadrant that the features center point lies within.
Origin Short explanation of name.