USGS Home
Contact USGS
Search USGS

• Home
• About
  • Project Descriptions
  • Landsat Updates
  • Mission History
  • International Landsat Ground Stations
  • USGS Landsat Ground Stations
• Gallery
• Products
  • Landsat Standard Data Product
    • USGS Archive and Available Scenes
    • Search and Download
    • Processing Details
    • Using Landsat Data
    • Satellite and Sensor Information
  • LDCM Data Specifications
  • Global Land Survey (GLS) 2005
  • Web-Enabled Landsat Data (WELD)
• Science
  • Landsat Science Team
    • Introduction
    • Responsibilities
    • Team Meetings
    • Team Publications and Presentations
  • Calibration
    • L7 ETM+ Calibration Files
    • L7 ETM+ Calibration Notices
    • L5 TM Calibration Files
    • L5 TM Calibration Notices
    • L4 TM Calibration Files
    • Definitive Ephemeris
    • Anomalies
    • LDCM Cal/Val Activities
  • Science Users Handbook
  • Data Gap Studies
• Tools
  • Featured Tools
  • Acquisition
  • Project Documentation
  • Converters & Shape Files
  • Glossary & Acronyms
  • FAQs
• Links
  • Affiliates
  • Education and Outreach
  • Reference
  • View, Search, and Order
• Contact

Frequently Asked Questions about the Landsat Missions

• What is Landsat and when did it begin?
• Where can I locate historical documents relating to the Landsat missions?
• What future missions are planned?

• What is the orbit path of Landsats 7 and 5?
• What is the Worldwide Reference System (WRS)?
• What are the band designations for the Landsat satellites?
• How are acquisitions planned for Landsats 7 and 5?
• Can an acquisition request be made for a specific date and location?
• How can I find the acquisition time for an image?
• Why is the thermal band on Landsat 7 (band 6) acquired in both low and high gain?

• Where can I find the latest information about Landsat data products?
• After a scene is collected, when will it become available for search and download?
• How do I search and download Landsat scenes?
• How do I search and download ascending (nighttime) scenes?
• After submitting a request for processing, how long before I can download the data?
• What files will be provided with a Landsat scene?
• What are the naming conventions for Landsat MSS, TM and ETM+ scene identifiers?
• Are there any restrictions on the use or redistribution of Landsat data?
• Are all collected Landsat scenes held in the USGS Landsat archive?
• What is Landsat 7 ETM+ SLC-off data?
• How do Landsat 7 ETM+ SLC-off data products compare to previous Landsat 7 data?

• What band combination is used for Landsat browse images?
• Why is there so much color variation among the Landsat browse images?
• Why do some browse images have a color shift midway through the scene?
• Why do some Landsat browse images appear pixilated?
• Why are some browse images black? (Earth Explorer)
• What is a Partial Aperture Calibration (PAC) scene?
• How is the percentage of cloud cover calculated?
• Why is the cloud cover reported as "0.00" for night scenes?
• Why are there gridlines on the SLC-off browse images?

• What is definitive ephemeris?
• How are the non-functioning detectors on Landsat 4 handled in processing?
• How do I fill in the gaps in my SLC-off image?
• How were the gaps filled in SLC-off scenes?
• What is the geometric accuracy of a Landsat 7 ETM+ systematically corrected Level 1G processed product?
• Does Landsat Level 1 processing include atmospheric correction?
• What is the difference between LPGS and NLAPS processing?
• How do I determine the processing level of the Landsat scene I have downloaded?

• How are the number of lines and samples (rows, columns) determined for a scene?
• What are the common anomalies found in Landsat data?
• Why are there lines across my Landsat TM image?

• How accurate is the radiometric calibration of Landsat images?
• What are Calibration Parameter Files?
• What is the difference between the CPF Effective date and Version date?
• What is a gain change?
• What is the difference between the 6L (low-gain) band and the 6H (high-gain) band?
• How is radiance calculated?
• How is at-sensor reflectance calculated?
• How is at-sensor temperature calculated for the thermal infrared bands (6L and 6H)?
• What is the minimal change in temperature that is detectable by the Landsat 7 thermal bands?

• What are the best spectral bands to use for my study?
• Can Landsat MSS images be compared to Landsat TM and ETM+ images?
• How does the orientation of an image affect the use of image processing software packages?
• What could be causing the "seamline" in a mosaic of multiple images?
• If gap mask files are not provided with the data, can I create my own?
• What is pan-sharpening and how can I create a pan-sharpened image?

• What are the processing levels for Landsat data?
• What are the differences in the data format options?
• What is the difference between path-oriented (nominal, satellite) and map-oriented (north-up) images?
• What is Level 0Rp processing?
• What is L1R processing?
• What is Level 1G, 1Gt, 1T SLC-Off processing?
• What is Level 1G, 1Gt, 1T Interpolated processing?
• What is Level 1G, 1Gt, 1T Gap-filled processing?
• What is Level 1T Segment-based Gap-fill processing?
• Which images will work best to fill in the gaps?
• What is the number of bits for the Level 1 radiometric (L1R) product?
• How can the acquisition dates of SLC-off fill scenes be determined?
• What is Modulation Transfer Function Compensation (MTFC) resampling?
• What are the descriptions for the levels of processing?
• How do the Raw reformatted and Radiometrically corrected data compare visually?