Landsat Images

There are over 160 Landsat images from all over Australia and selected overseas countries included on the CD. There are two Landsat scenes for each location, captured at different dates up to twenty years apart. The images have been processed so that they cover exactly the same area at the two dates. Thus the image at either date may be viewed or alternatively you may view a composite of the two dates. The difference images, created by subtracting the later images from the earlier image have also been included as a separate file.

The names of the files are based on the WRS numbering scheme which is adopted world-wide to uniquely identify Landsat scenes. Many of the scenes are subsets of full landsat scenes. Where there is more than one subset from the same scene, the filenames have an extra character (A, B, C etc) following the WRS number. Click here for a map of Australia with the WRS grid.

Image files for a particular location are named according to the WRS number of the later image, with the earlier and later image combined in one file and a separate difference image file. Image pairs and Difference images are distinguished by an "i" or a "d" following the WRS number. In most cases a location set consists of six files:

 Example filename  Description
 090085i.bsq  composite image - early and late scene combined
 090085i.hdr  composite image header - text file containing image parameters
 090085i.lis  info file - text file containing geocoordinates etc
 090085d.img  difference image - late scene subtracted from early scene
 090085d.hdr  difference image header - text file containing image parameters
 090085d.lis info file - text file containing geocoordinates etc

The composite images (image pairs) have six channels:

 Channel 1  MSS band 4  Early image  Blue
 Channel 2  MSS band 5  Early image  Green
 Channel 3  MSS band 7  Early image  Red
 Channel 4  MSS band 4  Late image  Blue
 Channel 5  MSS band 5  Late image  Green
 Channel 6  MSS band 7  Late image  Red

The difference images have three channels, derived from the composite images:

 Channel 1 (d) = channel 1 (i) - channel 4 (i)
 Channel 2 (d) = channel 2 (i) - channel 5 (i)
 Channel 3 (d) = channel 3 (i) - channel 5 (i)