GSE2GSM:

The gse2gsm program converts satellite data from the GSE coordinate system to the GSM coordinate system.  


There are two files to this program: gse2gsm.pro and gse2gsminput.txt.  gse2gsm.pro is the program itself, and gse2gsminput.txt is an input file, in which information is stored to be used by the program.

To use this program, you must first put the required information in the input file.

Open gse2gsminput.txt.  It should look like this:


	file:
	
	format:  day,month,year,hour,minute,second,x,y,z
	
	beginline:
	
	endline:
	
	outputfile: name of the file gsm data is saved to


Lines 1,3,5,7, and 9 are just headers; the program doesn't read them.  You will have to fill in the information for lines 2,4,6,8, and 10.  


Line 2:  The filename and path of the file with GSE data.  It should look something like this:
/home/f03/yourname/gsedata.txt


Line 4:  The IDL format code for the data.  Each row of data has several pieces of data: the time, and the x,y,z GSE coordinates.  The time consists of day, month, year, hour, minute, and second.  Each element is a seperate piece of data that is read by the program.  Format codes tell the program what characters to read as data, and which characters are not data.

There the three different format codes that need to be used for this program:

iN		an integer value, N is the number of character positions for the given integer

fN.M		a floating point value, any number with a decimal point, N is the total number of character positions for the number, 		including the decimal point and negative sign.  M is the number of character positions after the decimal point, don't 		use it if different rows of data have different numbers of decimals.

Nx		a non-data point.  N is the number of character positions to be skipped.

Each format code should be separated by a comma, and the whole thing should be in parentheses.

Example:

25-12-2004/08:22:36.264     -2355.1236        23203.8     -225790.99
25-12-2004/09:22:36.264     -4346.3688      20387.444        -225790
25-12-2004/10:22:36.264       -6383.56       17225.85     -225790.34
25-12-2004/11:22:36.264     -8374.5688     14863.8326     -225790.63

(i2,1x,i2,1x,i4,1x,i2,1x,i2,1x,f6.3,f15,f15,f15)

*note the last three codes are f15 instead of f9.4 because different entries have different numbers of decimal places, and the program can read spaces as long as the number you are trying to read is within the format code.


Line 6:  The first line with data on it.  Press F11 to see line numbers in KWrite.  The entry here should look like:
163


Line 8:  The last line with data on it.  Should look like:
2005


Line 10:  The name of the file you want the GSM data saved to.  Don't name it something you don't want overwritten.  Should look like:
gsmnewdata.txt



Once the input file is ready, save it.  Open a terminal program and start IDL by typing IDL.  Run the gse2gsm program by typing gse2gsm.  The output file should be saved to your home directory.