User Manual - pancroma

74. Tutorial – Pan Sharpen Gap Filled Images________________________________________________________________This tutorial describes the process for creating a natural color Landsat image byfirst gap filling and then pan sharpening the gap filled input files. The describedprocedure will create four matched multispectral bands and a matchedpanchromatic band for each of the two file sets: the Reference set (the one withgaps) and the Adjust set (the one without the gaps that will be used to correct theReference set.) I used a pair of Landsat scenes from Row 91 and Path 76 insouthern New Zealand for this example.The first step is to assemble your five Reference images and five Adjust images:a set of four multispectral bands and a panchromatic band for each. Themultispectral bands should include the blue, green, and red and near infrared(NIR) Landsat bands. You will need an exactly matched set of files.PANCROMA TM provides the necessary subsetting and resizing utilities toproduce these. The process will occur in four steps: subsetting, resizing, gapfilling, and finally pan sharpening.To start, select 'File' | 'Open' and open the first file set (you can use either theReference or the Adjust set). You must open them in the precise order: blue(band1), green (band2), red (band3) panchromatic (band8) and NIR (band4) inyour Landsat set. Now select 'Band Combination' | 'Subset Images' | 'Subset FiveBands'. After a bit of processing, the Subset Data Entry box will be presented.Subset the five bands simultaneously by any of the usual means for cornerselection: rubber band box, pixel coordinates or latitude and longitudespecification. Save the images by selecting 'File' | 'Save Subset Images' |'GeoTiff' (or whatever format you like) and supplying a base file name like'reference'. Select 'Close Graphics Window and Reset'. (Note: the images will notbecome visible until the 'Save' operation.Now open the second set of five band files as described above. The Subset DataEntry box will again become visible. Notice that the pixel coordinates and thelatitude and longitude values from subsetting the first set of images are still in thetext boxes. This will allow you to select the same geographical area in thesecond set that you selected in the first set. Since the two Landsat scenes willdiffer somewhat in size and in area covered, you cannot select the second set bypixel coordinate value. Instead, select the 'Select by Coordinates radio buttonand then select 'Enter'.Note that if you select a subset area in the second set that is outside of thegeographic extents of the first set (something that is easy to do if you select anarea near the image edges) then you will not get a matching subset. This isbecause PANCROMA TM will truncate the selection in order to prevent inputtingillegal coordinates. PANCROMA TM has a feature to automatically select the full345