Remote Sensing

Remote sensing is the technique of collecting information from a distance that may range from hundreds of feet (aerial photography) to thousands of miles (weather satellites).  Currently, most natural resource mapping is accomplished by interpreting and classifying remotely sensed imagery.  For many decades, aerial photography has been an extremely valuable tool for the natural resource manager.  Soil survey and forest resource assessment programs have relied on the use of aerial photography since the 1930s, when black-and-white air photos were first being used for these activities.  Since then, black-and-white and color infrared aerial photography has been used quite extensively to produce topographic, forestry, geology, land use, and soils maps.  More recently, a variety of satellite sensors, and airborne radar, scanner, and video systems have been used for these types of mapping applications.  The use of modern remote sensing systems for natural resource monitoring and mapping applications allows for the uniform acquisition of digital data over large geographic areas. 

For those who are not familiar with remote sensing data and its many uses may want to refer to The Remote Sensing Tutorial, an online handbook sponsored by NASA'sGoddard Space Flight Center, Applied Information Sciences Branch (Code 935).  This online handbook is a complete primer on the subject of remote sensing.  It covers a wide variety of topics including the historical and technical background of remote sensing; digital image processing and classification techniques; and the use of various satellite platforms for geologic, vegetation, urban and land use, meteorological and oceanographic, and extraterrestrial applications.  This online tutorial defines all the important remote sensing terms, includes numerous sample images and spectral band comparisons, and is also available on CD-ROM for $10. 

The most frequently utilized sources of remotely sensed data for monitoring and mapping Minnesota's forest resources are the Landsat Multispectral Scanner (MSS) and Thematic Mapper (TM) sensors; the Advanced Very High Resolution Radiometer (AVHRR) sensor; and black-and-white and color infrared aerial photography.  The following links will take you to summaries of these sources of remotely sensed data.  These summary pages also include links to detailed metadata records and sources of data.

In addition, these links will take you to summaries of two key programs that rely heavily on remotely sensed imagery: