Geoscience Reference
In-Depth Information
Sensor (TIRS). h ese two sensors provide coverage of the global landmass at
spatial resolutions of 30 meters (visible, NIR, SWIR), 100 meters (thermal),
and 15 meters (panchromatic) (Ochs et al. 2009, Irons et al. 2011). General
information concerning the Landsat program can be obtained from the
webpage
http://landsat.gsfc.nasa.gov/?page_id=7195
Landsat data, together with data from other NASA satellites, can be obtained
from the webpage
http://earthexplorer.usgs.gov
On this webpage we i rst select the desired map section in the
Search Criteria
,
either by entering the coordinates of the four corners of the map or by
zooming into the area of interest and selecting
Use Map
. As an example we
enter the coordinates 4°42'40.72"N 36°51'10.47"E of the Chew Bahir Basin in
the Southern Ethiopian Rit . We then choose
L8 OLI/TIRS
from the
Landsat
Archive
as the
Data Set
and click
Results
. Clicking
Results
produces a list
of records, together with a toolbar for previewing and downloading data.
By clicking the
Show Browse Overlay
button we can examine the images for
cloud cover. We i nd the cloud-free image
Entity ID: LC81690572013358LGN00
Coordinates: 4.33915,36.76225
Acquisition Date: 24-DEC-13
Path: 169
Row: 57
taken on 24th December 2013. We need to register with the USGS website,
log on, and then download the Level 1 GeoTIFF Data Product (897.5 MB),
which is then stored on the hard drive in the i le
LC81690572013358LGN00.
tar.gz
. h e
.tar.gz
archive contains separate i les for each spectral band as
well as a metadata i le containing information about the data. We use band 4
(Red, 640-670 nm), band 3 (Green, 530-590 nm) and band 2 (Blue, 450-510
nm), each of which has a 30 m resolution. We can import the 118.4 MB TIFF
i les using
clear
I1 = imread('LC81690602013150LGN00_B4.TIF');
I2 = imread('LC81690602013150LGN00_B3.TIF');
I3 = imread('LC81690602013150LGN00_B2.TIF');
Typing
