GOMAG

Magnetometer file handling and plotting


Introduction

This page details IDL routines which have been written to plot IAGA format magenetometer data files. The routines can be acessed directly within go or by running gomag.

The gomag script is located in the directory /people/cutlass/idl/image. On running the script several of the go FUNCTIONS and PROCEDURES are stripped by the UNIX sed command to produce a subset of the go routines.

FUNCTION axis_time
FUNCTION no_ticks
PRO time_axis_intervals
PRO set_window
PRO set_window_size
PRO clear_page
PRO plot_window
PRO define_panel
PRO get_device_colours
PRO set_format
PRO set_time_format
PRO ALL postscript routines except ps_plot_page

The Arguments supplied to the routines are listed as for go; those in curly parenthases {} are optional. Where several options are mutually exclusive, they are separated by |. Some arguments must be supplied in string form, ie. encapsulated in ''. Arguments in square brackets [] indicate arrays.


gomag routines

magfile,['file 1','file 2',...,'file n'] or 'file1', {dir=directory}

The files are required to be in IAGA format and have a ".iaga" extansion. The location of the required file can be defined by setting dir (e.g. dir='/cutlass/data/image/'). The default is to search the directories defined by the SD_MAGOPEN_PATH environment variable.

plot_mag , comp=['x','y','z'] or /all {columns,rows,column,row, , filt=['x','y','z'], time=[start,end], /Pi2, station='station', high=high, low=low, /noMean,/showmean,scale=[] }

The components to be plotted are defined by the comp=['x','y','z'] array. If the data is in H,D and Z format then the components should be referenced by X,Y and Z respectively (e.g. comp=['x','y'] will plot the X and Y or H and D components depending of the data format). The keyword /all will set comp=['x','y','z'],thus producing a plot of all three components.

The columns, rows, column, row, usage is the same as for Plotting maps and RTIs.

Setting the keyword /noMean will plot absolute components (i.e. the components mean value is not removed) the default is to zero mean the data.

Setting the keyword /showmean will plot on the right hand y-axis the mean value removed from the trace.

The station name may be set by the station='station' option. A table of some of the station names is included in the software. To determine whether the station name is held in the table then use maginfo.

The plot_mag procedure also alows filtering of the data by setting the high and low options (the values are in seconds). Setting only the high and low values will filter and plot the components specified in the comp array as well as plotting the unfiltered component values. To plot only filtered values set the filt array with the same reference values as for comp and NOT the comp array. Setting the keyword /Pi2 sets the filter values high and low to 200 and 20 seconds respectively. If the comp and filt arrays are unset and the /Pi2 is set then all three filtered components will be plotted (i.e. plot_mag, /Pi2).

The time axis of the plot will either be set as for the last call of set_rti_limits or maybe set with time=[start,end] where start and end have the form hhmm. If there is no SDARN data loaded or the time has not been set the default is to plot the entire data set.

The keywords /no_x and /no_y suppress labeling of the x and y axis.

no_x can take a number of values which are additive

0 Plot full axis
1 Remove text from time axis
2 No internal x-axis when components plotted
4 Remove lower axis(and text) of plot frame
8 Remove upper axis of plot frame

The array scale allows the setting of the absolute scale around zero for each of the plotting panels. The array must either contain the same number of parameters as the keywords comp and filt with the comp scale values first (e.g. comp=['x','y'],filt=['x'] then scale=[10,10,5]) OR the array can be for the above example scale=[10,5,-1] or scale=[10,-1] which will set the scale for both comp and filt to 10.

plot_magarray, xmaps,date=date,time=time,scale=scale, comp=comp,filt=filt,pi2=pi2,high=high, low=low,no_y=no_y,spanel=spanel,array=array, greenland=greenland,image=image,charsize=charsize, /finfo,dir=dir,/find

All keywords and parameters not described below are the same as for plot_mag.

array can be a single string value or array of values corresponding to the three letter station id code of the magnetometer station.

greenland and image can be used to plot the greenland and image stations

Setting the find keyword enables the program to search the SD_MAGOPEN_PATH to determine the stations avaliable for the array before plotting. SD_MAGOPEN_PATH can be set with mag_path and examine with listmag_paths

date is a six character value or array of values representing the date (e.g. 960626). This parameter coupled with the stcode provides the information for the files that should be read.

charsize sets the size of the characters employed on the time axis

xmaps in this case specifies the number components to be plotted next to each other on a page.

Setting finfo will plot the filtering information.

maginfo

Returns information about the location of the magnetometer station stored in the IAGA file (see the IAGA format ) and the name of the station (from the three letter identification code) if it has been defined within the software.

magcat,{search,dir='directory'}

Returns a catalogue of magnetometer data from the directories defined by the system variable SD_MAGOPEN_PATH or in the directory specified by dir='directory'. The files are identified only if they have a ".iaga" extension. The serach string can be used to narrow the search parameters i.e. magcat,9606 will search for data in June 1996

mag_path,'path_name'

The path_name will be added to the search environment variable SD_MAGOPEN_PATH if it does not already exist and will be removed if already specified.

listmag_paths

Lists the environment variable SD_MAGOPEN_PATH.


SuperDARN documentation