User Manual - pancroma

14. Display_____________________________________________________________Zoom OutSatellite band images are large. Often it is convenient to zoom out in order tobetter inspect input band files. PANCROMA TM allows you to zoom out and thenback in to your color or grayscale input and processed images. In order todemonstrate with a grayscale image, open a file by selecting ‘File’ | ‘Open’.Select ‘Display Files’ | ‘Display One Grayscale Band Image’. When the filedisplays in the graphics window, the zoom menu selections are enabled. Select‘Display’ | ‘Zoom Out’. Your grayscale image will zoom to half its original size.Successively selecting the ‘Zoom Out Grayscale’ feature will increase the zoomfactor by 2. In order to return to the original zoom factor, select ‘Display’ | ‘ZoomIn’. The Zoom Factor is displayed at the top of the Main Window when zoomingis enabled.Note that if you save your image at other than full scale (Zoom Factor=0)PANCROMA TM will zoom back to the original scale so that the image will matchthe metadata.Note also that zooming is relatively fast, except for images that exceed 100million pixels (like Landsat panchromatic bands for example). In order to avoidrunning out of memory resources, the initial zoom out or the last zoom in will takeconsiderably longer as a result of the memory management technique used.Zoom InYou can also zoom into a color or grayscale image. To demonstrate this with agrayscale image, create a grayscale image by opening a band file by selecting‘File’ | ‘Open’ and ‘Display Files’ | ‘Display One Grayscale Band Image’. Whenthe file displays in the graphics window, select the zoom center by clicking on apixel. When you select a pixel, the zoom menu selection will be enabled. (Youcan click on the image as many times as you want. The zoom center will refreshto the new location after each click. Now Select ‘Display’ | ‘Zoom In’. A newgraphics window with your zoomed image will appear with a zoom ratio of two. Ifyou wish to zoom in further, click on the new (Zoomed) window and select‘Display’ | ‘Zoom In’ again. The image will zoom in by a factor of four.Successive clicking and zooming will allow you to create as many zoom levels asdesired.Note that the coordinates of the zoom image map back to the source image.This is important for spectral analysis where selected individual pixels need to beidentified and selected for processing. When you are done zooming, you canclose the Zoom Window by clicking the ‘X’ in the upper right corner of the image.26