User Manual - pancroma

13. System Variables_____________________________________________________________Information MessagesPANCROMA TM will normally provide system information messages designed tohelp the user understand what kind of input the selected utility is expecting. Forexample, when you select ‘Band Combination’ | ‘Generate RGB True ColorComposite’ PANCROMA TM generates an information message box informing youthat it expects the band files input in the order blue, green and red.Other utilities have their own message boxes that confirm the order of entry, filetype, file number and file size details. If you do not wish to have these messageboxes presented, you can turn them off by selecting ‘System’ | ‘InformationMessages’ | ‘Off’ from the Main Menu screen.File Size VerificationPANCROMA TM has several input file size and type sentinels. These aredesigned to prevent operating system access violations by over writing or overreading internal array boundaries. In general, PANCROMA TM has three levels offile sentinels, plus a fourth menu enabling check. When there is more than oneinput file, the first level checks to see if all the input files are the same size. Thesecond level checks that the file characteristics are correct, for example, that thefile is uncompressed, the bits per sample is 8, the planar configuration is either 1or 2, etc. The third level checks to make sure if the row and column counts allmatch up.The fourth level is controlled by the menu enabling logic. PANCROMA TM tries topresent only those menu selections that are consistent with the characteristics ofthe opened files. If the files are not consistent, it can cause an untrapped error.These are usually caught by the operating system but at best they would causePANCROMA TM to crash by over writing an array or some similar misbehavior.24