ESRI is the world leader in GIS (geographic information system) technology. This site features free GIS software, online mapping, online training, demos, data, software and service information, user scripts, and more.
This learning module includes activities that analyze water (oceans, rivers, watersheds, wetlands, etc.) within an explicitly spatial context. As the author of the module, Joseph Kerski states: "Water is a spatial subject: It easily moves among its solid, liquid, or gas phases on our planet. It flows through oceans, rivers, wetlands, glaciers, and through the hydrologic cycle at different rates. Thus, the geographic perspective and GIS are useful to understanding water from local to global scales. These activity use ArcGIS Online, a Web-based Geographic Information System (GIS). No previous experience with GIS is necessary."
Via Seth Dixon