The topics

3D 3D virtual globe Access Control aerial images Analysis analytics API App application schema Are3na Atom atomfeed authoring Availability Azores batch Big Data broker cache Cadaster Capacity testing catalog Client cloud services CMS code list code lists controlled vocabulary coordinate systems coverage crawler Crowdsourcing CSW customisation database DCAT DCAT-AP diagrams Disaster Management Documentation Dublin Core Earth Observation EASIN edge-matching ETF ETL event Extension Fires gazetteer Generator geocoding geodata management GeoDCAT-AP geometric algorithms Geometry Validation geonode geoparsing geoportal geoprocessing geoserver GEOSTAT geostatistics geotagging GeoXACML globe GML GPS GPX grid harvesting HILUCS hosting INSPIRE INSPIRE central component INSPIRE dataset INSPIRE Discovery Service INSPIRE Download Service INSPIRE Geoportal INSPIRE metadata INSPIRE pre-defined WFS INSPIRE theme INSPIRE View Service INSPIRE WCS Reference Implementation interoperability IP ISA ISO 19115 ISO 19119 ISO 19135 ISO 19139 JSON KML KPI layer LDAP LiDAR Linked Data manifestation map MARC 21 mashups MDI-DE MetaCRS metadata metadata editor metadata quality metadata template Metocean modelling Monitoring multi-dimensional mygeoss NASA Natura 2000 NetCDF noise OAI-PMH observations OCL OGC OGC Compliance Program Open data OpenGL OpenSearch ortho-rectification OSGeo Outdoor PDOK performance photogrammetry PID pilgrimage planar partitions portrayal projections proxy QGIS Quality of Service RASTER RDF Register registry Remote Sensing rendering reporting RESTful API retrieval reverse geocoding RoR routing SaaS Scenario 1 schema.org schema transformation Schematron SDI SDK search engine SEMIC sensor sensor data management SensorML shop simulations SKOS SOS SPARQL spatial analysis spatial index spatio-temporal Statistics Survey SVG SWE thesaurus THREDDS TMS Tourism trail transformation transport UML Usage validation Validator vector VGI Viewer Visualisation Water Framework Directive water management WCS weather forecast WebGL web metrics WFS WMC WMS WMTS WPS XSLT

Proj4J is a Java library to transform point coordinates from one geographic coordinate system to another, including datum transformations.

The core of this library is a port of the  PROJ.4 C library. The projection algorithms and coordinate system definitions are ported from PROJ.4. These are wrapped in a Java class model which follows standard Java conventions and OO best practices, and which provides a convenient domain model for working with coordinate systems.

Among its featuresÑ