Essentials of Physical Geography Author:Robert E. Gabler, James F. Petersen, L. Michael Trapasso ESSENTIALS OF PHYSICAL GEOGRAPHY emphasizes three essential themes to demonstrate the major roles for the discipline--Geography as Physical Science, Geography as Spatial Science, and Geography as Environmental Science. With a renewed focus on examining relationships and processes among systems, the text helps you understand how the various syste... more »ms interrelate.« less