Tools and Data
ImageJ is a public domain Java image processing program inspired by NIH Image for the Macintosh. It runs, either as an online applet or as a downloadable application, on any computer with a Java 1.1 or later virtual machine. ImageJ can display, edit, analyze, process, save and print 8-bit, 16-bit and 32-bit images. It can read many image formats including TIFF, GIF, JPEG, BMP, DICOM, FITS and "raw." It supports "stacks," a series of images that share a single window, and animation. It can calculate area and pixel value statistics of user-defined selections. It can measure distances and angles. Images can be zoomed up to 32:1 and down to 1:32. All analysis and processing functions are available at any magnification factor. Spatial calibration can be set to provide real world dimensional measurements.
Free: This software is in the public domain.
Landsat satellites "view" Earth at seven different wavelengths. Color images are created from the satellite data by assigning red, green, or blue light to the views of three different wavelengths, then combining them into one image. The resulting image is called a false-color image because it uses red, green, and blue to show features as they appear at some other wavelength. The Landsat images used in this chapter show bands 5, 4, and 2 in red, green, and blue light, respectively. This combination provides a fairly close simulation to what would be seen with the human eye.
NASA's Scientific Visualization Studio at Goddard Space Flight Center scaled and registered the images so that all three of them show the exact same area at exactly the same scale. This pre-processing step involved adjusting the size of the images and cropping them.