ESRI is a major US company in the Geographic Information Systems, mainly for government and business. >Coordinate systems, map projections, and geographic (dat

ESRI is a major US company in the Geographic Information Systems, mainly for government and business. >Coordinate systems, map projections, and geographic (datum) transformations >Every dataset has a coordinate system, which is used to integrate it with other geographic datasets within a common coordinate framework. Coordinate systems enable you to integrate datasets to perform various integrated analytical operations, such as overlaying data layers from disparate sources and coordinate systems. Geographic, projected, and vertical coordinate systems, as well as geographic (datum) transformations, are discussed in this topic. http://resources.esri.com/help/9.3/arcgisengine/dotnet/89b720a5-7339-44b0-8b58-0f5bf2843393.htm http://resources.esri.com/help/9.3/arcgisengine/dotnet/89b72... >US datum modernization coming in 2022 https://community.esri.com/groups/coordinate-reference-systems/blog/2019/02/26/us-datum-modernization-coming-in-2022 https://community.esri.com/groups/coordinate-reference-syste...