Proj.4

Proj.4 is an open-source software library used for converting geographic coordinates between different map projections. Map projections are methods to represent the Earth's curved surface on flat maps, and each has unique distortions. Proj.4 allows geospatial applications to accurately transform coordinates from one projection system to another, ensuring precise mapping, navigation, and spatial analysis. It's widely used in GIS (Geographic Information Systems) to handle various coordinate systems, enabling consistent and reliable map data across diverse datasets and mapping standards.