In this first section of Week 8, you'll review some of the basic GIS skills you have learned, including turning layers on and off, zooming and panning within them, and working with the data tables linked to the map.
Launch My World by double-clicking its icon on your desktop or by clicking its icon in the Dock (Mac) or Launch Bar (Win).
Choose File > Open Project..., navigate to My World/data/AspenFireMW.m3vz, select the AspenFireMW.m3vz file, and click Open.
When the project opens, the base map displays a satellite image of Earth.
The image is part of the Blue Marble collection at NASA. It is a composite generated from several different types of data. Much of the data comes from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument, a remote sensing device on the Terra satellite. Latitude and longitude lines are visible on top of the image.
Select the Zoom In tool and drag a rectangle over Arizona.
Here is what the map looks like after zooming in on Arizona.
Now turn on the Landsat Mosaic layer and make it active by clicking its name in the Layer List. Then click the Zoom to Active Layer button.
Here is what the map looks like after zooming in on the Landsat Mosaic layer.
Continue working your way up the list through the Layer List, turning on each layer and zooming in as needed to see it. Stop when you get to the True Color Aerial layer. This layer displays a remotely sensed image of the Aspen Fire. Read the passage below to find out about the Aspen fire.
The Aspen Fire started on Tuesday, June 17, 2003, in the Catalina Mountains north of Tucson, Arizona, about two miles from the mountain community of Summerhaven. The fire spread rapidly, fueled by high temperatures and dry conditions and fanned at times by extremely high winds gusting at 40 to 60 miles per hour.
When the summer monsoon rains finally arrived on July 15, the fire was extinguished. By that time the fire had burned 84,750 acres and destroyed 335 structures. Three and a half million gallons of water were used to fight the fire, 400,000 gallons of fire retardant were dropped, and over 1000 fire fighters battled the blaze. The cost of suppressing the fire was estimated at 17 million dollars.
Turn on the False Color Aerial image. Switch between the True and False color images by turning them alternately on and off.
These remotely sensed images of the Aspen fire were acquired on June 24, 2003 by the MODIS Airborne Simulator instrument carried by a NASA ER-2 high altitude aircraft. (The ER-2 is a research version of the military U-2 spy plane.) MODIS is capable of imaging in 36 different wavelength bands, including several bands in the infrared (IR).
The bottom image is a true color image, approximating what you would see if you looked down on the fire from the plane. The top one is a false color image with Shortwave IR assigned to the red channel, Near IR assigned to green, and Green assigned to the blue channel. Notice how the addition of the infrared wavelengths makes the extent of the burned area easier to detect. The red color does not represent the heat of the fire. Rather, it's the high reflectance in the shortwave IR from the now barren trees and ground. The fire itself appears as bright orange-red strips around the perimeter of the burn area. Note also how well the infrared wavelengths penetrate the smoke, giving a much clearer picture of conditions on the ground.
Living vegetation strongly absorbs at these IR wavelengths and reflects green light, so vegetated areas appear bright green in the image. Rocks and bare ground appear brownish.
Remotely sensed images and GIS data were instrumental in monitoring both the fire and its aftermath. In general, images like these are helping natural resource personnel to better understand and manage fires.
Move your way up the Layer List and explore the other layers in the project by turning them on and off and zooming in or out as needed. To speed up the time it takes for layers to load in the map, you can turn off the images that you are not using.
Use the Zoom and Move Map tools as you explore.
Zoom In Zoom Out Zoom to Active Layer Move Map Zoom Full Extent
When you are done exploring, turn off all the layers except the False Color Aerial and Shaded Relief images.
Investigate Tables of Layers in the Aspen Fire Project
Open and investigate several of the Table of Layers for data layers in the project. As you investigate these layers and their data, think of questions that you might be interested in exploring further, such as: "How did the fire spread?" or "Where was the greatest damage?"
Turn on the Daily Fire Perimeter and zoom in until you can clearly see the perimeter lines. Then make this layer active.
Open the Table of Layer of Daily Fire Perimeter and sort the records by DATE in ascending order. The dates are given in a month and day combined format. For example, June 28th is listed as 628.
Click once on the Daily Fire Perimeter label in the Layer List and then select the Show Table of Active Layer button.
In the Table of Layer "Daily Fire Perimeter" window that opens, you can view the individual records for the layer. Scroll across the table until you find the DATE field.
Select the header of DATE field. Click on the header to rearrange the records in the table in chronological order, either ascending or descending. The dates are given in a month and day combined format. For example, June 28th is listed as 628.
Each record in the Table of Layer "Daily Fire Perimeter" describes a specific polygon on Earth's surface that was burned by the fire over a one day period and corresponds to a feature on the map. In this case, these polygons show the progress of the fire each day. They contain important information for fire management planning. They show direction and rate of the fire's spread. They are drawn frequently throughout the day by the fire management team. Fires generally slow their progress during the night, giving the fire crews time to recoup and use these maps to plan a strategy of attack for the next day. These maps are also posted in places where they are publicly available, so that everyone involved has the opportunity to be informed.
Move the Table of Layer "Daily Fire Perimeter" so you can see both the table and the map at the same time. Click any record in the table, and click "Make Selection from Rows". Give your selection a name or accept the default name applied, (you can change it later if you wish). Click OK and the corresponding feature will be highlighted in yellow on the map, although some features are so small that they might be hard to see.
Select records in groups by day to follow the daily progression of the fire. When selecting records, use the shift key to select a group of perimeters showing each day's records as a group. Then click the "Make Selection from Rows" button, rename your selection with the date of the fire selected. When you are finished investigating, close the attribute table of the layer.