Kohasüsteem

Kohasüsteem refers to a system of locating and identifying specific geographic positions. It is a fundamental concept in cartography, surveying, and geographical information systems (GIS). A kohasüsteem defines how locations on the Earth's surface are represented mathematically and how different maps or datasets can be accurately overlaid or compared.

The core components of a kohasüsteem include a geodetic datum, a map projection, and a coordinate system. The geodetic datum provides a reference frame for measuring locations, often based on a specific ellipsoid model of the Earth. Map projections translate the curved surface of the Earth onto a flat plane, inevitably introducing some distortion. The coordinate system then assigns numerical values (e.g., latitude and longitude, or Easting and Northing) to points within that projection.

Different kohasüsteemid are used globally and regionally, each with its own advantages depending on the intended application and geographic area. Common examples include the World Geodetic System (WGS) 1984, widely used for GPS, and various national or local systems like the Estonian Coordinate System (EKG). Understanding the specific kohasüsteem of a dataset is crucial for accurate spatial analysis, data integration, and precise navigation. Errors in defining or using the correct kohasüsteem can lead to significant spatial inaccuracies.