Frequently Asked Questions (FAQs)

 

Landsat Program Frequently Asked Questions are available on the Landsat website.

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Project Frequently Asked Questions

 

Are there costs associated with using the SouthFACT applications?

If I create an account, will my contact information be distributed in any way?

Can I submit a Custom Request outside the SouthFACT project area (i.e., outside the Southeastern US)?

How far back can a Custom Request be made for?

How large an area is covered by a Landsat image?

What’s the Landsat change product / image resolution?

How often can each image change?

How many images can change in a day?

Does the Forest Change Viewer update daily?

 

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FAQ Responses

 

Are there costs associated with using the SouthFACT applications?

No. The SouthFACT project has been developed in the public domain. All applications, desktop tools, and project code are free to use.

 

If I create an account, will my contact information be distributed in any way?

No. User email addresses are only used for the application to provide subscription alerts when new change products are available and to deliver download links for custom request products. Organization name and type provide the SouthFACT team with the ability to summarize usage statistics and quantify the benefits of the project.

 

Can I submit a Custom Request outside the SouthFACT project area (i.e., outside the Southeastern US)?

Not at this time. The application currently restricts the acquistion of raw imagery from the EROS Data Center to the 142 World Reference System (WRS) - 2 path / row areas that intersect one or more of the 13 Southern Region states. Please see the Project Overview page for more information.

 

How far back can a Custom Request be made for?

The SouthFACT project is designed to use Landsat 5, Landsat 7, and Landsat 8 imagery, allowing requests to go as far back as March 1984. However, it should be noted that there are slight differences in wavelength ranges measured across Landsat platforms. These differences can potentially make interpretation of change products more confusing when comparing across platforms.

 

How large an area is covered by a Landsat image?

A standard WRS-2 path / row tile covers a land area approximately 115 miles (185 kilometers) in an east-west direction (across-track) by 112 miles (180 kilometers) in a north-south direction (along-track). This is equivalent to a land area of approximately 8,243,200 acres in size.

 

What’s the Landsat change product / image resolution?

The spatial resolution of Landsat imagery is primarily 30 by 30 meters. SouthFACT products are also 30 by 30 meters. Therefore, each image pixel is approximately 0.22 acres in size.

 

How often can each image change?

Potentially, every eight days. Landsat 7 and Landsat 8 each have a 16 day return, which means that each satellite captures an image of the same location on Earth every 16 days. However, L7 and L8 orbits are offset by eight days. With the SouthFACT project analyzing imagery across platforms as frequently as possible, updated change products could be based on an eight day window.

 

How many images can change in a day?

SouthFACT monitors 142 WRS-2 path / row areas. At most, 23 of them could change on a given day.

 

Does the Forest Change Viewer update daily?

Potentially. New Landsat imagery is acquired on a daily basis. Some portion of the project area will have new imagery from Landsat 7 and / or Landsat 8. However, the SouthFACT project currently screens new imagery to exclude data that is greater than 87.5% cloud covered. Therefore, if all new scenes have very high cloud cover, the Forest Change Viewer will not incorporate the new imagery.