Page 70 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

34 Chapter 1 essentials of Geography
Burned area
Yellowstone National Park boundary
Geyser field
Lake Old pine forest
(a) In this January 12, 2014, image, pink and white areas are (b) After the bushfires, this January 28, 2014, image shows the farmlands, green areas are forested, and lakes appear black. extent of burnt areas in red in the northern part of Grampians
National Park and adjacent farmlands. The area burned was about 53000 hectares; for scale, the scar is approximately
25 km x 30 km.
▲Figure 1.29 Effects of bushfires in Grampians National Park, Victoria, Australia. Landsat-8 images contrast the landscape at the Grampians before and after bushfires on January 15, 2014, using a combination of visible and near-infrared radiation. [USGS.]
in complex ways never before possible. Whereas printed maps are fixed at time of publication, GIS maps can be easily modified and evolve instantly.
In a GIS, spatial data can be arranged in layers, or planes, containing different kinds of data (Figure 1.31). The beginning component for any GIS is a map, with its associated coordinate system, such as latitude–longitude provided by GPS locations or digital surveys (the top layer in Figure 1.31a). This map establishes reference points against which to accurately position other data, such as remotely sensed imagery.
▲Figure 1.30 Suomi NPP blue Marble image. This composite view of earth was imaged January 2, 2012. NASA scientist Norman kuring combined VIIRS instrument data from 6 orbits of the Suomi NPP satellite. VIIRS acquires data in 22 bands covering visible, near- infrared, and thermal infrared wavelengths. [NASA.]
Firehole River
Grand Prismatic Spring
Old Faithful
CRiTiCAlthinking 1.5 Test Your Knowledge about Satellite Imagery
Go to the USGS (eros.usgs.gov/) or eSA (european Space Agency; www.esa.int/Our_Activities/Observing_the_Earth) website and view some satellite images. Then examine the image in Figure CT 1.5.1. Was this made by an aircraft, a ground-based sensor, or a satellite? Is this a natural- colour or false-colour image? Can you determine what the colours represent? Can you identify the location, the land and water bodies, and other physical features? Fi- nally, based on your research and examples in this text, can you determine the specific source (liDAR aircraft, GOES or Landsat satellite, etc.) of the data that made this image? (Find the answers at the end of the Chapter 1 key learning Concept Review.) •
▲Figure CT 1.5.1 Can you describe this image? [NASA.]