racerxdl / channelmuxer.py

#!/usr/bin/env python import sys, struct, os HEADERTYPE_MAP = { 0: "Primary Header", 1: "Image Structure", 2: "Image Navigation", 3: "Image Data Function", 4: "Annotation", 5: "Timestamp", 6: "Acililary Text", 7: "Key Header", 128: "Segment Identification", 129: "NOAA Specific", 130: "Header Structured Record" } for i in range(8,128): HEADERTYPE_MAP[i] = "Reserved" for i in range(131,256): HEADERTYPE_MAP[i] = "Reserved" filename = "channels/53/1702_0_1311_1.lrit" f = open(filename, "r") fsize = os.path.getsize(filename) readbytes = 0 t = 0 def readHeader(f): global t type = ord(f.read(1)) size = f.read(2) size = struct.unpack(">H", size)[0] data = f.read(size-3) t += size if type == 0: filetypecode, headerlength, datalength = struct.unpack(">BIQ", data) print "Header type: %s (%s) File Type Code: %s Header Length %s Data Field Length: %s" %(type, HEADERTYPE_MAP[type], filetypecode, headerlength, datalength) elif type == 1: bitsperpixel, columns, lines, compression = struct.unpack(">BHHB", data) print "Image Structure Header: " print " Bits Per Pixel: %s" %bitsperpixel print " Columns: %s" %columns print " Lines: %s" %lines print " Compression: %s" %compression elif type == 2: projname, cfac, lfac, coff, loff = struct.unpack(">32sIIII", data) print "Image Navigation Record" print " Projection Name: %s" %projname print " Column Scaling Factor: %s" %cfac print " Line Scaling Factor: %s" %lfac print " Column Offset: %s" %coff print " Line Offset: %s" %loff elif type == 3: print "Image Data Function Record" print " Data: {HIDDEN}" #print " Data: \n%s" %data elif type == 4: print "Annotation Record" print " Data: %s" %data elif type == 5: print "Timestamp Record" days, ms = struct.unpack(">HI", data[1:]) print " Delta from 1 January 1958" print " Days: %s" %days print " Miliseconds: %s" %ms elif type == 6: print "Ancillary Text" print " Data: %s" %data elif type == 7: print "Key Header" print " Data: %s" %data elif type == 128: print size imageid, sequence, startcol, startline, maxseg, maxcol, maxrow = struct.unpack(">7H", data) print "Segment Identification Header" print " Image Id: %s" %imageid print " Sequence: %s" %sequence print " Start Column: %s" %startcol print " Start Line: %s" %startline print " Number of Segments: %s" %maxseg print " Width: %s" %maxcol print " Height: %s" %maxrow elif type == 129: print "NOAA Specific Header" signature, productId, productSubId, parameter, compression = struct.unpack(">4sHHHB", data) print " Signature: %s" %signature print " Product ID: %s" %productId print " Product SubId: %s" %productSubId print " Parameter: %s" %parameter print " Compression: %s" %compression elif type == 130: print "Header Structured Record" print " Data: %s" % data else: print "Type not mapped: %s" % type print "" data = f.read(10) filecounter, Transportlength = struct.unpack(">HQ", data) print "File Counter: %s Transport Size: %s" %(filecounter, Transportlength) readHeader(f) readHeader(f) readHeader(f) readHeader(f) readHeader(f) readHeader(f) readHeader(f) readHeader(f) readHeader(f) readHeader(f) print t f.close()