Step 1
Load the image!

Step 2
Enhance contrast

Step 3
Select a band combination

Step 4
Georeference the image

Step 5
Enhance resolution

Step 6
Enhance sharpness

Step 7
Create maps and graphics

Step 1 - Load the Image!

Satellite images, like most other types of image or graphical data, is typically obtained in digital format on CD-ROM, DVD, or via direct download over the Internet. Unlike graphics that illustrate web pages, however, satellite image files are usually pretty big -- 300 megabytes is not uncommon, vs. 20 kilobytes for a web graphic.  The raw image data are encoded in a “binary raster” format that can only be manipulated and displayed using software specifically designed for image processing.

We use a variety of software here at SkyTruth, but the image-processing workhorse for us is Erdas Imagine. When beginning the process we load the image data from the CD-ROM or another location onto the image processing workstation. This image is oriented parallel to the satellite’s orbital path, not “north up,” and is not in any particular map projection.

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Raw, unenhanced satellite image:  yucko.