Coordinate System and Map Projection

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Coordinate System and Map Projection

Map as input data, information representation model and data analysis result model is an important part of GIS. A map is a picture of part or all of the earth's surface, both above and below the surface and presented on a flat plane at a certain scale and projection (mathematically). There are 2 coordinate systems that are generally used in the preparation of geographic information systems, namely the geographic coordinate system and the Universal Transverse Mercator (UTM) coordinate system.

Geographic Coordinate System

The Geographic Coordinate System consists of latitude that divides evenly from the equator towards the poles and longitude that divides the equator evenly.

Figure 3 above shows the coordinates of Moscow City (yellow spot) in DMS and DD coordinates. Decimal Degrees (DD) is related to Degrees/Minutes/Seconds (DMS), by changing the minutes and seconds values into 'decimal degree values'. Decimal Degrees are generally more widely used because they are easier to calculate and use in other applications.

Universal Transverse Mercator (UTM) Coordinate System

The shape of the earth is almost spherical, while for mapping purposes it is necessary to depict it in a flat plane with controlled distortion, so a projection system is needed. One of the most widely used map projections for mapping purposes is the Universal Transverse Mercator (UTM) projection.
The UTM projection was made by the US Army in the 1940s and has since become the standard for topographic mapping. The UTM projection has the following properties:
1. This projection intersects the globe on two meridians, which are called standard meridians. The             meridian at the center of the zone is called the middle meridian.
2. The area between these two meridians is called the zone. Zone width is 6 degreesSo the globe is             divided into 60 zones.
3. The magnification at the middle meridian is 0.9996, the magnification at the meridian
        the standard is 1 and the magnification at the peripheral meridian is 1.001.
4. The unit of measurement used is the meter.
5. To avoid negative coordinates in the UTM projection, each middle meridian in each zone is priced         at 500,000 mT (eastern meters).
6. For values towards the north, the equator is used as a datum line and is assigned a value of 0 mU            (meters north). For calculations to the south of the equator, the value is 10,000,000 mU.

UTM Zone Division Worldwide


UTM Coordinate Value




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