For ease of use in mapping the entire surface of the planet conditionally divided into zones of lines drawn from pole to pole.Axial called the meridian passing through the center of each zone.Total received 60 such zones, ieeach "slice" orange earth has to 6 ° of longitude.This allows the coordinates of points on the earth's surface to calculate the serial number of the zone, and for it to calculate the latitude and the central meridian zone.
Define the sequence number (n) zone.The countdown begins with units from the Greenwich meridian.Because each zone has to 6 ° longitude, divide evenly longitude (L) of the coordinates of any point you ar
e interested in the area and increase the output per unit: n = L / 6 ° + 1. For example, if on a sheet of card, the next meridian that youinterest, a point with the longitude of 32 ° 27 ', so this sheet belongs to (32 ° 27' / 6 °) Zone 6 = +1.
for determining longitude (L₀) central meridian area obtained in the previous step sequence number, multiply by 6 °, and of the result subtract 3 °: L₀ = n * 6 - 3 °.For example used above the central meridian longitude is equal to 6 * 6 ° -3 ° = 33 °.
Russia has a unified coordinate system SC-95 points the state geodetic network, fixed on the ground on measurements at the era of 1995 to determine the spatial or plane rectangular coordinates of the central meridian on the assumption that the pointcount each zone is located 500 kilometers west of the intersection of the central meridian with the equator.
The geodetic rectangular coordinate systems equator line is considered to be the x-axis (X), and the parallel line of the meridians - the vertical axis (Y).Often, however, when building objects using conventional coordinate system in which the directions of the axes are selected, for example, on the route of the railway.This should be considered when determining the central meridian area using such cards.