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Baidu Coordinate System (BD09), also known as Baidu Coordinate System, is a coordinate system developed by Baidu to meet the special needs of geographic information systems in mainland China. It is encrypted based on the WGS84 coordinate system (World Geodetic System 1984) to ensure accurate geographic positioning services within mainland China.

ETRS89 is the reference coordinate system for measurement and geographic information in Europe. Its goal is to establish a unified spatial reference frame across Europe.

Geographic Coordinate System (GCS) is a coordinate system based on a sphere or ellipsoid that is used to define locations on the surface of the Earth. It describes a location using two angular coordinates (usually latitude and longitude), and the third value can be an optional altitude value. GCS is widely used in fields such as geographic information systems (GIS), mapping, and navigation, and is the basis for expressing geographic data.

NAD83 (North American Datum 1983) is a geographic coordinate system (geographic reference system) widely used in North America, especially in the United States, Canada, and Mexico. It is a modernized, high-precision version of the previously used NAD27 (North American Datum 1927), developed with a focus on compatibility with GPS technology. Its EPSG code is 4269.

**SIRGAS 2000 **is a geocentric reference frame for Central and South America, which aims to define and implement a unified reference frame for Central and South America that is consistent with ITRF. Its ellipsoid adopts GRS 1980, with a major semi-axis of 6378137 meters, an oblateness of 298.257222101, the Greenwich meridian as the prime meridian, and the angle unit is degree. SIRGAS 2000 was established in 2000, consistent with the ITRF2000 framework, with a reference epoch of 2000.0. It is a regional encryption of ITRS in South America, achieved through a network of about 200 continuously operating stations (SIRGAS-CON) throughout Latin America and the Caribbean.

ED50 is a European geodetic datum established in 1950. It is based on the overall adjustment of the European triangulated network and adopts Clarke ellipsoid parameters. It is mainly used for topographic surveying, mapping and early geographic information system (GIS) applications in Europe.

JGD2011 is a modern geocentric coordinate reference frame established by Japan in the early 21st century to replace the old Tokyo Datum (such as Tokyo 1918). Its core is based on the GRS80 ellipsoid, with the origin aligned with the center of mass of the earth, and the coordinate axis pointing in accordance with international standards (such as the prime meridian passing through Greenwich). This framework is implemented through space geodetic technologies such as GNSS and VLBI, with an accuracy of centimeters. It can dynamically reflect plate movement and earth deformation, and is suitable for high-precision geographic positioning needs in Japan and surrounding waters, and is gradually connected with international coordinate systems (such as ITRF).

MGI coordinate system was established by the Austrian Military Geographical Institute. It is a local coordinate system based on the Bessel ellipsoid and is mainly used for geographic information representation and spatial positioning in Austria. It uses the Transverse Mercator projection, with the central meridian at 13°20′ east longitude, the latitude of the projection origin at 0°, the easting offset of 1,500,000 meters, and the northing offset of 0 meters. It is a variant of the Gauss-Krüger projection and is widely used in Austria in many fields such as topographic mapping, land management, urban planning, and transportation planning, providing an accurate spatial reference frame for these fields.

CH1903 is the widely used national coordinate system of Switzerland, based on the geodetic datum established in 1903. It is a projection coordinate system covering the whole of Switzerland, developed to enable precise geospatial information management and mapping of a country with mountainous terrain. The reference ellipsoid used is Bessel 1841, and the projection method is the Oblique Mercator Projection. This coordinate system has long been used by the Swiss National Cartographic Office (Swisstopo) and has become a standard in many fields such as topographic mapping, surveying, civil engineering and infrastructure planning. In recent years, Switzerland has gradually transitioned to the higher-precision CH1903+ (EPSG:2056) coordinate system, but a large amount of historical data is still stored based on CH1903.

PZ-90 (Parameters of the Earth Ellipsoid 1990) is a georeferenced coordinate system developed by Russia for its global navigation satellite system GLONASS.