TerraColor® Frequently Asked Questions (FAQ)

1. How do I determine which image tiles I need?
2. What is simulated true color?
3. Why is TerraColor more colorful than some true color imagery?
4. Is TerraColor 'pan sharpened'?
5. Is TerraColor used in Microsoft's web mapping applications?
6. Is Harris Corp's Globe15 product based on TerraColor?

1. How do I determine which image tiles I need?
Click on this link to download the image coverage Shapefile showing the boundaries of each TerraColor image tile to determine the number and filenames of tiles you need to cover a specific area of the earth.

2. What is simulated true color?
To create 'true color' imagery, you must use the visible wavelength bands (3, 2 and 1) of the Landsat 7 sensor. TerraColor was created from bands 7 (middle infrared), 4 (near infrared) and 2 (visible green), then the colors were transformed using a proprietary process to simulate land and water colors that are close to those of true color imagery. Since all the information needed to create a true color image is not present in bands 7, 4 and 2, TerraColor has a slightly different look and information content than true color imagery. True color imagery has superior water color and depth information, while TerraColor's simulated true color has superior vegetation and geology information. The use of infrared bands in the development of TerraColor also reduces cloud and haze problems that can be pronounced in true color imagery, resulting in more consistent, higher contrast imagery.

3. Why is TerraColor more colorful than some true color imagery?
TerraColor was designed to simulate the colors of the earth when viewed on a clear, sunny day at low altitude. Therefore, it is often more colorful than true color imagery of the earth taken from high altitudes where atmospheric haze tends to attenuate or diminish the colors. So TerraColor tries to simulate the "close up" colors of the earth versus the "far away" colors of the earth.

4. Is TerraColor Pan-sharpened?
Yes it is. Pan sharpening is a process that fuses or merges the higher resolution (14.25-meter) panchromatic band of Landsat 7 with the lower resolution (28.5-meter) color/multispectral bands to create color imagery at 14.25-meter resolution.

5. Is TerraColor used in Microsoft's web mapping applications?
An older, modified version of TerraColor is used as the medium resolution satellite imagery in Microsoft's web mapping applications. The imagery is displayed whenever you see "Earthstar Geographics LLC" displayed in the lower-right corner of the mapping window.

6. Is Harris Corp's Globe15 product based on TerraColor?
Yes, Harris Corporation licensed an earlier version of the TerraColor product from us, and did their own color modifications tailored to their visual simulation market. They sell this product commercially under the brand name Globe15.

| TOP |