# the following is a python script translated for the C code for LITE L1 data # The first part shows the structure of the data # the the script shows an example of how to output the 4 variable types # char, shor, long and float # Use the readme_little_endian.docx file to get the byte numbers of the desired variables # To run this script it takes one argeumnt of the file name # I.e. LITElittle_endian.py LITE_L1_19940919_054004_054158 # Created on : Jun 26, 2025 """ /*level 1 structure*/ struct { short syncvalue; /*always 12345*/ char majorversionnumber; char minorversionnumber; char datatakeid[7]; /*ascii description*/ char orbitnumber; long idnumber; /*unique record id*/ short gmtday; /*greenwich mean time*/ char gmthour; char gmtmin; char gmtsec; char gmthund; short metday; /*mission elapsed time*/ char methour; char metmin; char metsec; char methund; float latitude; /*degrees*/ float longitude; /*degrees */ float shuttlealtitude; /*kilometers*/ float offnadirangle; /*degrees*/ float digitizerondelay; /*useconds*/ char datatakemode; /*0=day 1=night*/ char specialopsmode; /*0=normal 1=multiscatter 2=gainchange 3=transition*/ char profilevalidstatus; /*0=valid 1=355quest 2=532quest 4=064quest*/ /*8=355invalid 16=532invalid 32=064invalid*/ char landwaterflag; /*0=land 1=water*/ float surfelevfootprint; /*kilometers*/ float metdataalts[18]; /*kilometers*/ float mettemps[18]; /*kelvin*/ float alttropopause; /*kilometers*/ float temptropopause; /*kelvin*/ char laserselected; /*0=a 1=b*/ char baalignmentstatus; /*0=not aligned 1=aligned*/ char isdbstatus; /*0=invalid 1=valid*/ char badatastatus; /*0=invalid 1=valid*/ char aodatastatus; /*0=invalid 1=valid*/ char motorinmotion; /*0=stopped 1=motion*/ char aperwheelstatus; /*0=closed 1=large 2=annular 3=small 4=motion*/ char backgroundmongain; /*0=day 1=night*/ char surfacemode355; /*0=no 1=yes*/ char dbattenuation355; /*db*/ short numbersatabovesurf355; /*num samples*/ float highestsatsample355; /*kilometers*/ short numberunderflows355; /*num samples*/ char filterstatus355; /*0=out 1=in 2=motion*/ char calibrationstatus355; /*0=estimated 1=calculated*/ float calibrationfactor355; char baselinerippleremvd355; /*0=no 1=yes*/ char oscillationremoved355; /*0=no 1=yes*/ char backgroundvalue355; /*raw value from instrument*/ char highvoltage355enabled; /*0=disabled 1=enabled*/ float highvoltage355; /*volts (355 nm measured high voltage)*/ float energymonitor355; /*mjoules*/ float pmtgain355; char baselinesubmethod355; /*0=slope 1 = averaged*/ char subregionunderflow355; /*0=none 1=underflow in baseline subtraction region*/ char anomalousprof355; /*0=normal 1=anomalous*/ char fillbyte1; char surfacemode532; /*0=atmospheric 1=transition 2=surface*/ char dbattenuation532; /*db*/ short numbersatabovesurf532; /*num samples*/ float highestsatsample532; /*kilometers*/ short numberunderflows532; /*num samples*/ char filterstatus532; /*0=out 1=in 2=motion*/ char calibrationstatus532; /*0=estimated 1=calculated*/ float calibrationfactor532; char baselinerippleremvd532; /*0=no 1=yes*/ char oscillationremoved532; /*0=no 1=yes*/ char backgroundvalue532; /*raw value from instrument*/ char highvoltage532enabled; /*0=disabled 1=enabled*/ float highvoltage532; /*volts (532 nm measured high voltage)*/ float energymonitor532; /*mjoules*/ float pmtgain532; char baselinesubmethod532; /*0=slope 1 = averaged*/ char subregionunderflow532; /*0=none 1=underflow in baseline subtraction region*/ char anomalousprof532; /*0=normal 1=anomalous*/ char fillbyte2; char surfacemode064; /*0=atmospheric 1=transition 2=surface*/ char dbattenuation064; /*db*/ short numbersatabovesurf064; /*num samples*/ float highestsatsample064; /*kilometers*/ short numberunderflows064; /*num samples*/ char filterstatus064; /*0=out 1=in 2=motion*/ char calibrationstatus064; /*0=estimated 1=calculated*/ float calibrationfactor064; char baselinerippleremvd064; /*0=no 1=yes*/ char oscillationremoved064; /*0=no 1=yes*/ char backgroundvalue064; /*raw value from instrument*/ char highvoltage064enabled; /*0=disabled 1=enabled*/ float highvoltage064; /*volts*/ float energymonitor064; /*mjoules*/ float pmtgain064; char baselinesubmethod064; /*0=slope 1 = averaged*/ char subregionunderflow064; /*0=none 1=underflow in baseline subtraction region*/ char anomalousprof064; /*0=normal 1=anomalous*/ char fillbyte3; char timeedsinthour; /*unadjusted eds time*/ char timeedsintmin; char timeedsintsec; char timeedsinthund; char level0fileidnumber; /*level 0 directory number*/ char level0fileidletter; /*level 0 file letter*/ char reserved[6]; float highvoltage355cmd; /*volts (355 nm commanded high voltage)*/ float highvoltage532cmd; /*volts (532 nm commanded high voltage)*/ char reserved2[4]; float b0_355; /*baseline subtraction value*/ float b0_532; /*baseline subtraction value*/ float b0_064; /*baseline subtraction value*/ char outofrng355abv40; /*0=none,1=underflow,2=overflow,3=underflow and overflow*/ char outofrng532abv40; /*0=none,1=underflow,2=overflow,3=underflow and overflow*/ char outofrng064abv40; /*0=none,1=underflow,2=overflow,3=underflow and overflow*/ char outofrange355[375]; /*packed bit array for underflow or overflow*/ char outofrange532[375]; /*packed bit array for underflow or overflow*/ char outofrange064[375]; /*packed bit array for underflow or overflow*/ short top355; /*index of highest valid count*/ short bottom355; /*index of lowest valid count*/ short top532; /*index of highest valid count*/ short bottom532; /*index of lowest valid count*/ short top064; /*index of highest valid count*/ short bottom064; /*index of lowest valid count*/ float profile355[3000]; /*counts*/ float profile532[3000]; /*counts*/ float profile064[3000]; /*counts*/ } astruct; """ import sys # used to get input argument # function to translate the hex number into a 32 bit float def GetFloat32(HexNumber): # determine if data is negative or positive negative = (HexNumber & 0x80000000) if negative == 0: sign = 1 else: sign = -1 # determine the exponent exponent = (HexNumber & 0x7f800000) >> 23 # Subtract 127 from the exponent exponent -= 127 # Convert the mantissa into decimal using the last 23 bits power = -1 total = 0.0 for i in range(1,23) : c = (HexNumber & (pow(2,23-i)))>>(23-i) total += (c * (pow( 2.0, power ))) power=power-1 total= total + 1.0 value = sign * ( pow( 2.0, exponent )) * total return (value) # end of GetFloat32 function # setup the file input and output before reading the file # set up file name as an input argument filnme = sys.argv[1] f=open(filnme,'rb') # create output filename from input name filnmout = (filnme)+ '_64.out' print(filnmout) flout = open(filnmout,'w') flout.write(" GMT_Day Time Latitude Longitude \n") # read file by strucutre size until EOF reached while True: # read one full structure of size 37500 astruct = f.read(37500) if not astruct: # continue reading until end of file break syncvalue = (astruct[0]<<8) | astruct[1] if syncvalue != 12345: printf("bad syncvalue\n") sys.exit(0) # setup the time variables of char type with one byte from structure gmthour = astruct[18] gmtmin = astruct[19] gmtsec = astruct[20] gmthund = astruct[21] # sample process for long variables using idnumber with 4 bytes 12, 13,14 and 15 idnumber = ((((((astruct[12]<<8)+astruct[13])<<8)+astruct[14])<<8)+(astruct[15])) # sample process for getting GMT day of short variables of 2 bytes 16 and 17 gmtday = ((astruct[16]<<8)+astruct[17]) # Sample process For getting float variables of 4 bytes #Bytes 28, 29, 30 and 31 for latitude tmplat = ((((((astruct[28]<<8)+astruct[29])<<8)+astruct[30])<<8)+astruct[31]) # For float variables need Next line to translate character into a 32-bit float latitude = GetFloat32(tmplat) tmplong = ((((((astruct[32]<<8)+astruct[33])<<8)+astruct[34])<<8)+astruct[35]) # For float variables need Next line to translate character into a 32-bit float longitude = GetFloat32(tmplong) # write data to file flout.write(f"{gmtday:2}, {gmthour:02d}:{gmtmin:02d}:{gmtsec:02d}.{gmthund:02d}," ) flout.write(f" {latitude:.8f}, {longitude:.8f} \n" ) # close the two files f.close() flout.close()