User Manual - pancroma

You can use the 'Max Cloud' drop down menu to eliminate scenes with excessivecloud cover. The ideal case is when both the Reference and Adjust images have0% cloud cover. Selecting this will of course limit the number of scenes that youcan select from. However for many parts of the earth there are multiple cloudfreescenes available. Once you have found an appropriate Adjust image,download the blue, green and red bands. It is recommended that you set up a filestructure to keep everything straight during the subsequent operations.Landsat images are acquired at two different ground resolutions: 28.5m and30.0m. Often the Reference and Adjust images do not match, and it isnecessary to correct this. PANCROMA TM provides a utility for converting 28.5mto 30.0m resolution. Open a single band file and then select ‘Pre Process’ |‘Resize Images’ | ‘Scale Landsat 28.5m to 30m’. After the file is rescaled, save itby selecting ‘File’ | ‘Save’ | ‘Geotiff’. Repeat for the rest of the Adjust andReference band files.IMPORTANT NOTE: Landsat band files are archived in two resolutions: 28.5mand 30m. PANCROMA TM has a utility for scaling a 28.5m to 30m scale. Select'PreProcess' | 'Resize Images' | 'Scale Landsat 28.5m to 30m'. The utilitymultiplies the rows and columns by a factor of 28.5/30 and multiplies xScale andyScale by the inverse ratio.The next step is to subset and register the images. Landsat scenes, even if theyshare the same path and row numbers usually will not match exactly. If youwish to produce the largest possible image then you must determine the extentsof the area that is common to the two Landsat scenes. PANCROMA provides autility for determining this common area. To do this, load a band file from theReference scene, for example Reference band 1, by selecting ‘File’ | ‘Open’ andthen selecting the band file. Then open the corresponding band from the Adjustscene. Now select ‘Band Combination’ | ‘Subset Images’ | ‘Compute MaximumCommon Extents’. After a moment the corner coordinates of the largest areathat is common to both scenes will be displayed in the main text window. It is notnecessary to record these coordinates as PANCROMA TM will remember themautomatically for the next steps.Next you must subset both sets of band files to the computed corner coordinates.First load the three reference bands (blue, green and red). Select 'BandCombination' | 'Subset Images' | 'Subset Three Bands' from the main menu. Aftera moment a single grayscale image and subset form will appear. The cornercoordinates computed by the ‘Compute Maximum Common Extents’ utility havebeen automatically inserted into the coordinates text boxes in the Subset ImageForm. Check the ‘Select by Coordinates’ radio button and then select ‘Enter’.The first set of subset images will be computed. Save the images by selecting‘File’ | ‘Save Subset Images’ | ‘Geotiff’, saving the using an appropriate file name.(Suffixes will be automatically appended so you only need to specify the rootname.)322