User Manual - pancroma

Alternatively, you can enter the coordinates using the rubber band box. Click onthe ‘Rubber Band Box Select’ button and then use the mouse and the left mousebutton to identify the subset box. Finally, you can input latitude and longitudemanually. In order to switch from automatic coordinate entry to manual entry ofcoordinates into the text boxes, switch the radio button from ‘Select by Pixels’ to‘Select by Coordinates’. Automatic reporting will stop and the boxes will beenabled for manual entry.PANCROMA also provides a Subset Coordinate Report form that records the filenames, projection, datum and the corner coordinates. You can cut and pastethis information if you need to save it for subsequent image processingapplications.Although no subset images are yet displayed (or computed, for that matter), theprogram has recorded the key data to produce four subset images: one for eachof the band files and one for the PAN file. These images will be preciselymatched to each other, that is they will describe the exact same area of theearth’s surface. (The panchromatic image will of course have twice the lengthand width of the band images.)IMPORTANT NOTE: Clicking the ‘Enter’ button will not start the computations.These start when you save your images. When your selection is complete, youcan save the subset images to disk by selecting ‘File’ | ‘Save Subset Images’ andselecting .jpg, .bmp or .png format.The computations are done in this manner in order to conserve system RAMresources. This is necessary when your subset is almost the same size as theparent image. If computed immediately, both the image and the array data wouldconsume a lot of memory resources. By computing on ‘Save’, each band file iscomputed, written to disk, and the memory resources immediately freed. If the‘Display Subset Images’ box checked (default), the images will be displayed asthe image is saved as well.Since the resulting files are exactly matched, they can now be pan sharpenedexactly as described in the previous section for full Landsat images, only morequickly since they are of course smaller than the parent images.IMPORTANT NOTE: Even if you intend to pan sharpen the full Landsat image, itis generally a good idea to subset the image first in order to determine the bestimage processing settings. These settings of course can be retained after thesubset images are unloaded and the full band and panchromatic images areopened.40