Preface

Nowadays it is hard to find areas of human activity and development that have not profited from or contributed to remote sensing. Natural, physical and social activities find in remote sensing a common ground for interaction and development. From the end-user point of view, Earth science, geography, planning, resource management, public policy design, environmental studies, and health, are some of the areas whose recent development has been triggered and motivated by remote sensing. From the technological point of view, remote sensing would not be possible without the advancement of basic as well as applied research in areas like physics, space technology, telecommunications, computer science and engineering. This dual conception of remote sensing brought us to the idea of preparing two different books. The present one is meant to display recent advances in remote sensing applications, while the accompanying book is devoted to new techniques for data processing, sensors and platforms.

Strictly speaking, remote sensing consists of collecting data from an object or phenomenon without making physical contact. In practice, most of the time we refer to satellite or aircraft-mounted sensors that use some sort of electromagnetic radiation to gather geospatial information from land, oceans and atmosphere with increasingly high spatial, spectral and temporal resolutions. Space agencies in charge of collecting remotely sensed data have shown a notorious interest in making these data available for research and social development. The confluence of remote sensing technology with other sciences has resulted in an exponential growth of knowledge, technology development and assessment of all kind of physical and natural phenomena, as well as human activities that share a common ground: geospatial information. However, the success of remote sensing influencing other areas of knowledge and human activity has not always been a paved way. The variables of great interest to scientists in different areas are not readily available from the raw remotely-sensed data. Even when the data has been processed and converted to physical-related values, or even linked to human and natural artifacts like crop fields, roads, urban areas, geomorphologic structures, vegetation indices, etc., the relationship between these and the more abstract variables that explain them such as human settlement dynamics, geophysical phenomena, climate change, etc. remain a major field of study and research.

This book intends to show the reader how remote sensing impacts other areas of science, technology, and human activity, by displaying a selected number of high quality contributions dealing with different remote sensing applications. Twenty two chapters have been carefully collected and distributed in four areas. The first part deals with land cover applications, and contains applications in vegetation indices, crop and pest monitoring, rainfall and fire relationship with vegetation, change detection, soil salinization, modeling water and heat regimes, catastrophe assessment and lava flow mapping. The second part contains contributions on climate and atmosphere, including carbon and water dynamics, ocean evaporation, and atmospheric aerosols and clouds. The third part presents oceans and cryosphere applications that include aquatic vegetation, oil spill assessment, coral reef habitat mapping, water source predictability from snow maps, cryosphere study, and maritime search and rescue. Last but not least, the last part presents contributions dealing with human activity, including population estimation, archaeology, urban growth, medicine and healthcare and military applications.

I am indebted to all authors who have contributed to this book. Without their strongest commitment this book would not have been possible. I am also thankful to InTech editorial team who has provided the opportunity to publish this book.

> **Boris Escalante-Ramírez**  National Autonomous University of México, Faculty of Engineering, Mexico City, Mexico
