The values in this structure are established by the MAP_SET procedure the user should not change them directly. !MAPĪ variable containing the information needed to effect coordinate conversions between points of latitude and longitude and map coordinates. !FALSEĪ read-only variable containing the boolean value of false (0). !DTORĪ read-only variable containing the floating-point value used to convert degrees to radians (∏/180 0.01745). ![]() The value for ∏ (pi) was computed using Buffon's needle method with approximately 2 53 tosses of 4 cm toothpicks onto parallel lines.Ī read-only variable containing the double-precision value of ∏ (pi). The light-year distance was computed using the speed of light during 1 Julian year of 365.25 days*86400 seconds. The values for au, G, M_earth, M_sun, parsec, and R_earth are derived from the IAU 2009 System of Astronomical Constants, based upon the Barycentric Coordinate Time (TCB) values. ![]() The values for fundamental physical constants are taken from the Committee on Data for Science and Technology, "2010 CODATA Recommended Values," available from the Physical Measurement Laboratory at the National Institute of Standards and Technology (NIST). All values are in double precision and are given in Meter-Kilogram-Second (MKS) units. The following table lists !CONST names and values. The following image displays the colors described in the table above.Ī read-only structure variable that contains physical constants. The following table lists !COLOR names and values (these are essentially the same as those in W3C’s list of web colors): ![]() !COLORĪ read-only structure variable that allows you to retrieve color values by providing one of the color name strings listed in the table below. For example, the command: PRINT, ACOS(A) * !RADEGĬonverts a result expressed in radians to one expressed in degrees. System variables can be used just like other variables. The following system variables contain predefined constants or values for use by IDL routines.
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