Landsat 7 Long Term Acquisition Plan
The Long Term Acquisition Plan (LTAP7) is used to direct the acquisition of Landsat 7 scenes. These scenes are archived at the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center. A Landsat scene covers approximately 10,000 square miles (100 miles on a side) and is defined by a grid system called the Worldwide Reference System (WRS).
Five parameters are associated with the LTAP:
- Seasonality: – (Excel .xls (3.68 MB) -or- ASCII Text File - .lst (921 KB)) This file specifies which WRS scenes are to be acquired during which periods of time (request period), and the frequency of acquisition during those periods.
- Land Definition: – (Excel - .xls (1.5 MB)) The WRS Land Database lists all of the WRS path/rows that cover land and are considered part of the global archive.
- Geopolitical [country name; may also include the state]
- Geographical [for example: banks, rocks, shoals, reefs]
- Science identifier
- Examples
- Glaciers
- Oceanic islands of special science interest
- Reefs
- Tropical rainforest
- Historical Cloud Cover: – (Word text file - .doc (5.7 MB) and Word text file - .doc (5.7 MB)) The historical cloud cover reports the average cloud cover for each WRS scene for each month of the year.
- Gain Settings: – (ASCII text file - .lst (4.7 MB)) The gain settings file identifies the gain settings that will be used as defaults for each WRS scene for each day of the year. The default gain settings were generated using rules that take land cover type and sun angle into account.
- Sun Angle: The maximum solar zenith angle is used as a threshold during scheduling. Daylight imaging will not be scheduled if the solar zenith angle is equal to or greater than the maximum solar zenith angle value.
U.S. Department of the Interior |
U.S. Geological Survey
