Click a tile on the map below to view Landsat
7 imagery available for that particular Path & Row. This portal
to the US archive of ETM+ data is maintained by the RESAC
office of the Basic Science and Remote Sensing Initiative (BSRSI)
at Michigan State University. This system is an automated version of a
browse product display effort started with RESAC partners at the Environmental
Remote Sensing Center (ERSC)
at the University of Wisconsin - Madison. Try our global interface
at Landsat.org
Click on the map to view thumbnails of Landsat 7 imagery
Calculator
If you have latitude and longitude coordinates, you can use this USGS
calculator to identify the path and row of footprint(s) that overlap
any point on the globe. The calculator presents a world map showing the
location of the WRS-2 scene with its center point closest to the requested
coordinates. Conversely, you can enter WRS-2 Path and Row numbers and receive
the latitude and longitude of the scene center point. Works with both degree-minute
and decimal-degree formats.
Landsat
7 Path Acquisition Schedule
Want to know when Landsat 7 is passing over your area of interest? Identify
your "path" of interest using the calculator or reference map
above and scroll down the lookup table below to find the revisit dates for
Landsat 7. The table covers the Upper Great Lakes region (paths 19 - 30)
from July 1999 to January 2002. Wherever possible, the listed date of acquisition
links to a GOES weather satellite image for that day and time. These can
be used to assess general cloud cover on a particular date. Links to new
GOES images are added regularly. [Note: GOES updates have been suspended
pending functional modification of this feature. Try StripBuilder tool
to view regional cloud cover for specific dates through Preview
Tools above (-- sab 1 Nov 2000)]
We would like to credit our RESAC partners at the University of Minnesota
for the idea of linking path/row revisit dates with GOES imagery. See their
example at the TerraSIP
site.
Landsat 7 has a 16-day revisit cycle. It operates in a sun-synchronous,
near-polar orbit at a nominal altitude of 705.3 km (438.4 miles) measured
at the equator. The descending orbital node time is 9:45 AM +/- 15 minutes
local time at the equator. The satellite completes its repetitive circular
orbit every 98.9 minutes as the Earth rotates beneath it. It takes 233 unique
paths to cover the Earth's surface. In 16 days, the satellite traces all
233 paths twice (233 daytime descending and 233 nighttime ascending). This
creates an "interlacing" pattern with its paths that is visible
in the table below. In a single day, the satellite makes 15 daylight passes
(see this example).
Most scientific interest in Landsat imagery involves interpreting solar
reflectance off the surface of the land. Therefore nearly all scenes collected
are daytime scenes over land. Scientists studying thermal phenomena such
as volcanoes also utilize nighttime images in their research. Each pass
of the satellite generates "strips" of data that are "cut"
into scenes with row designations. It takes only 23.92 seconds for Landsat
7 to collect the data for each scene along its path. It passes from north
to south over the entire Upper Great Lakes region in about 2 minutes. Local
time of acquisition in the region depends on location within a given time
zone and the observance of daylight savings time. For example, Landsat 7
passes over Lansing, MI at about 16:15 GMT making it 11:15 AM EDT (in the
summer) and 10:15 AM EST (in the winter).
For more information on the WRS 1 & 2 (Worldwide Reference System, i.e.
path and row) and other orbital details visit the WRS
page of NASA's Landsat 7 site. Click here for a global
WRS-2 map of daytime scenes. To view an excellent interactive real-time
model of the orbital characteristics of Landsat 7 and many other satellites
try JTrack
- 3D. Also visit the USGS
Landsat 7 home page for data information.
Last Updated on 23-Mar-2002 22:09
Email: batzlis@msu.edu
Visitors since 01-Nov-2000