User Manual - pancroma

Begin by opening your seven Landsat reference bands in the order: band1,band2, band3, band4, band5, band6 and band7 by selecting ‘File’ | ‘Open’ fromthe main menu. Now select ‘Spectral Analysis’ | ‘Landsat Point SpectrumGenerator’ | ‘Six/Seven 8-Bit DN Bands’. The Band Display Selection Form willbecome visible. This form allows you to specify which band or band combinationyou want to use to identify your target pixels. If clouds are your target, band1 is agood choice, although other will work as well. Click ‘OK’ when you have selectedyour band.Now the selected band image will appear, along with the Point Spectrum Form.The main purpose of the Point Spectrum Form is to keep a running tally of yourselected points. It also controls the zoom feature in case you need to get incloser into your image to accurately identify your target pixels. Using yourcursor, successively click on the cloudy areas of the image until you havecollected a representative sample (You can choose as many as 50, but often youcan get by with far fewer.) I chose 18. When you are finished, select ‘OK’.Now the TOA Reflectance Data Form will become visible. Enter the SolarElevation Angle, Julian Day and TIR Gain Level corresponding to your imagefrom the Landsat metadata file. Check the ‘Retain Settings’ box so that theentered values will be saved for subsequent runs. See the section on thePANCROMA Point Spectrum generator TM for details. Now select ‘OK’ and thePoint Spectrum for your Reference image will be generated.The next step is to generate the mask. Select ‘Close Graphics Window andReset’ from the Main Menu. When you do so, the spectrum will close. Howeverthe average TOA reflectances will be stored for the next step.Re-open your seven Target band files as before by selecting ‘File’ | ‘Open’ fromthe main menu. Select ‘Spectral Analysis’ | ‘Landsat Spectral Analyzer’ |‘Six/Seven 8-Bit DN Files’ | ‘Euclidean Distance’.Note that there are seven track bars corresponding to the seven multispectralbands we have opened. The average reflectances are already set into thesetrack bars so no adjustment is required (unless you feel some is necessary).Check the ‘Retain Settings Between Runs’ check box. This will hold our SpectralCriteria settings in case you will need multiple runs to make your mask.Also check the ‘Create Mask’ check box in the Mask Group. When you do so,the Level Selection track bar in the will become enabled. You can generateeither a positive mask or alternatively a negative mask, which will black out all ofthe non-target pixels and retain the targets. This selection can be made by usingthe ‘Positive Mask’ (default) and ‘Negative Mask’ radio buttons next to the‘Create Mask’ check box.This track bar lets you specify how far away the Euclidean Distance vector canbe from the target and still be included in the mask. The higher the number from0 to 8, the farther the distance and the more pixels will be included in the mask.261