Remote sensing was commercialized long before GIS became a mainstream technology, but it was not until recently, when the two technologies joined forces, that remote sensing truly took off. GISystems require volumes of data, and data quickly becomes out-of-date. Thus, remote sensing has provided to GIS a means of acquiring up-to-date data for large geographic regions at relatively low cost (and GIS has provided the incentive to acquire upp-to-date imagery). In particular, when working in fields such as resource management, regional planning, oceanography, disaster management and, increasingly, urban development, you will find that remotely sensed data is a 'core' dataset. Thus, a GIS analyst should have a fundamental understanding of remote sensing, given the synergies possible between the two fields.

There are many sites devoted to remote sensing. NASA has produced a useful tutorial at the Goddard Space Flight Center which covers most of the fundamental concepts involved in satellite image interpretation and analysis (it contains some fairly technical details that you can skip over). The Canadian Centre for Remote Sensing also has a number of tutorials. ESRI's help pages for image classification in ArcMap 10.1.

This site has some very insightful interactive tools and overall discussions on the use of remote sensing (especially for land classification) and I highly recommend you review its content: The American Museum of Natural History's Center for Biodiversity and Conservation Remote Sensing and GIS. Another set of comprehensive resources is provided on the EDUSpace site developed by the European Space Agency (ESA). A paper (another) on topographic corrections to satellite images.

There are now a number of sites that allow you to view / download satellite data. The USGS has created the LandsatLook Viewer, while ESRI has created the Changematters Viewer (which includes a tutorial [tour] on how to use their system).

There is an ever-growing number of satellites collecting data that can be used in a GIS environment. A listing of many of the satellite names is provided on this FAQ site. A short video highlighting some of the global products produced using remote sensing (e.g., Global percipitation records); another one showing the three basic kinds of orbits satellites take, and the ground-swaths associated with each.

How do we see what we see? A TED talk. (7:59) (Huffington)

Learning objectives

• Understand primary data capture techniques: remote sensing and surveying;
• Recognize the four resolutions of remote sensors;
• Be familiar with the secondary data capture techniques of scanning, manual digitizing, vectorization, (soft copy) photogrammetry, and COGO feature construction;
• Understand the principles of data transfer, sources of digital geographic data, and geographic data formats

Text: Chapter 9 GIS data collection [Overheads: 1 per page; 3 per page]

Keywords: EMR, Spectral signatures, active / passive sensors, benefits (subpolygon info, cross boundary info, timely, etc.), NDVI