This tutorial explains how one can download Landsat images from the United States Geological Survey(USGS) website.There are no restrictions to downloading data from the site,however a statement of the data source when citing,copying or reprinting the data or images is requested.
The approximate scene size covered by the images is 170 km North-South by 183 km East-West .
Throughout this tutorial i will be using Mt.Kenya as my area of interest(AOI)
1.Visit the http://earthexplorer.usgs.gov/ website and log in or create an account if you have none.I already have an account so i will just log in.Its very easy to create one
2.There are many options for selecting the area of interest;
Search your area of interest in the text box and click ‘show’.My AOI is Mt.Kenya.
Thereafter click on the Adress to display a marker on the map as stated.
The path and row is used as a worldwide reference system(WRS).The path is the descending orbit of the satellite and each path is segmented into 119 row,from North to South.The Landsat MSS sensor has 251 paths while the Landsat TM and ETM has 233 paths for complete coverage.
If you know the coordinates of any point in your area of interest,then you can go to the https://landsat.usgs.gov/tools_latlong.php website to determine its Path/Row.
Enter the path and row and then click ‘show’.
Enter the name of the feature and then click show.
(d)Use of coordinates
This is my favorite method.Click on ‘coordinates’,then on ‘use map’.Thereafter select a polygon around your area of interest.
You can also use predefined areas(only applicable to features in U.S.A),or load a shapefile or a KML file.
For a shapefile make sure it is compressed into a single file using the ZIP archive file format and it must contain a shape format file (.shp), shape index format file (.shx), and attribute format file (.dbf). A shapefile may also include an optional projection format file (.prj).
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3.The next step is to download the image covering the area of interest.
Click on ‘Datasets’ and choose a landsat sensor from the Landsat archive
4.Click on ‘additional criteria’ and check/select appropriate options.For instance you would want to reduce the cloud cover to the minimum provided so as to increase the clarity of the data.
5.The final step is to view and download the results.
Click on the results tab,choose the desired epoch and click on download.
Choose Level 1 product;it contains all the bands and this is useful for carrying out analysis in a remote sensing software.