We often want to plot X,Y data from a simple file consisting of columns and rows. Here I discuss some of the tools I use to do this.

1. The basic plotting tools.
2. A table file and an operation with it.
3. A simple interactive XY extraction tool.
4. A high-level plotting script.

I have a variety of plotting tools, but there are two python codes that I find to be generally the most useful. The first is named pxy_SM_plot.py and the second is trs_plot.py. The "trs_" package is designed for the less general problem of visuallizing coordinate transformations, but it uses some nice examples of point labeling and maintaining proper aspect ratio, ect... and so I mention it here. The links above will give you sample calls to these codes, but here are two quick examples:

 

% pxy_SM_plot.py style.hetq-tz 0 360 86 91 SHOW 
% cat style.hetq-tz 
20160617 ACAM Data
HETQ (HET Parallactic Angle)
tz
UT20160617-hetq-tz.file
UT20160617-hetq-tz.file_1
UT20160617-hetq-tz.file_2

% trs_plot.py Style.file -30 30 -30 30 SHOW 
% cat Style.file  
X,Y Gaussian Data
X (0.0,5.0)
Y (0.0,12.0)
XY0.rst_plot

I define a table file to be an ASCII file with a header section. Some would refer to this as a flat file. I always offset the header of my files with the "# data" string. Here is an example of the first protion of a table file.

 

% head -15 hetAZindo_dec01.dat
Col01 = STRUCTAZ, structure azimuth from header                                   
Col02 = AZfromDEC, azimuth based on declination                                   
Col03 = HETQfromAZ, parallactic angle from structure azimuth                      
Col04 = HETQfromDEC, parallactic angle from structure azimuth based on DEC        
Col05 = DECDEG, declination in degree uni ts                                      
Col06 = STRUCTAZ - AZfromDEC                                                      
Col07 = HETQfromAZ - HETQfromDEC                                                  
Col09 = side of sky relative to meridian                                          
STRUCTAZ, AZfromDEC, HETQfromAZ, HETQfromDEC, DECDEG, AZdif, HETQdif, direction   
# data
	180.00 177.75   180.000 178.060   -4.306543 002.25 001.94  E     20161006T001036.7_acm_sci 
	180.00 177.75   180.000 178.060   -4.306543 002.25 001.94  E     20161006T001021.3_acm_sci 
	180.00 177.75   180.000 178.060   -4.306543 002.25 001.94  E     20161006T001032.8_acm_sci 
	180.00 177.75   180.000 178.060   -4.306543 002.25 001.94  E     20161006T001029.0_acm_sci 
	180.00 177.75   180.000 178.060   -4.306543 002.25 001.94  E     20161006T001025.2_acm_sci

The full file is in:  $scohtm/scocodes/XYplots_from_Tables/sample_files/T1

The first thing we have to do is use a tool to pull the columns we want to plot from the table file. The python tool colget.py is good for this. Suppose I want to plot column 2 of our table (named AZfromDEC) and plot it on the Y axis as a fuction of column 5 (named DECDEG) on the X axis. With colget.py I could pull two files, one for each variablem and I can name the files using the variable name:

 

% colget.py hetAZindo_dec01.dat 2 AZ1 N
% colget.py hetAZindo_dec01.dat 5 DECDEG N
% ls
AZ1  DECDEG  head.lines  hetAZindo_dec01.dat  S/
% head -5 AZ1
  177.75
  177.75
  177.75
  177.75
  177.75

In this way I can build the file:  dat.1 with my X,Y data:
% head dat.1
point g o 90
AZ(from DEC)
  -4.306543	  177.75
  -4.306543	  177.75
  -4.306543	  177.75
  -4.306543	  177.75

Then I make the style file: stayle.1 
$ cat style.1
Sample Azimuth Plot 
Declination (degrees) 
Azimuth (degrees) 
dat.1 

Finally I can make my plot!

% pxy_SM_plot.py style.1 -10 89 0 360 SHOW

Here is the plot we have generated with the two columns pulled from out table file. This plot of approximately 3500 poinst was generated in a couple seconds (not including the time we used building the files style.1 and dat.1). My inital Azimuth range was 0 to 360, but becasue I used the show() module I was quickly able to interactively reset the axes and make a nicer version of the plot. Why my azimuths run from 0 to 180 instead of 0 to 360 is another question all together! As a result of this little plot, I could quickly see that I had lost my Azimuth values between 180 and 360. I went to my routine "estimate_azhet_hetq" and quickly located the trouble: another misssed dollar sign in front of a variable name. But, the problem is now fixed!

The example in the previous section explains how things are done, but it is not very practical. What we want is a way to quickly extract columns from a file and build the plot file we need for pxy_SM_plot.py.Here is an easy-to-use tool for this:

 

% xy_from_table hetAZindo_dec01.dat 5 1  

* You are queried for the symbol style, marker symbol, color, etc... 
* the product is a file named XY.plot that can be fed to pxy_SM_plot.py

Here is the plot from the previous section where I have now fixed my azimuth problem. I have also added the AZSTUCT values obtained from ACAM images (these are plotted as small red dots). The plot files were easily generated with the script xy_from_table. The commands I used were: % xy_from_table hetAZindo_dec01.dat 5 1 % xy_from_table hetAZindo_dec01.dat 5 2 **** I manually create the style.1 file **** % pxy_SM_plot.py style.1 -10 89 0 360 SHOW Again, I note that I changed the plot limits on each axis using the show() module. The values at high azimuth were running in the point legend in the upper-right of the plot. With show() is was trivial to correct this on the fly.

Finally, I'll mention that "xy_from_table" has a little trick built in. You can read the plot info automatically if you build a local file named "xy_from_table.input" that has the necessary parameters written to it. This is not terribly useful for a single manual run, but as we'll see in the next section, it can be very useful for building a higher-level tool. Here is an example of using this mode:

 

% cat xy_from_table.input  
point r o 50 "My Comment"

[sco@mcs T1]$ xy_from_table hetAZindo_dec01.dat 5 1

[sco@mcs T1]$ head -5 XY.plot
point r o 50
"My Comment"
  -4.306543	  180.00
  -4.306543	  180.00
  -4.306543	  180.00

I have developed a fairly simple script for doing all of the tasks discussed above.

I have plotted four rather large data sets from a single ASCII file using the "xyplotter" code. [sco@mcs T1]$ cat List.axes Multiple Plots -12 100 Declination (degrees) 0 360 Azimuth , HETQ [sco@mcs T1]$ cat List.1 hetAZindo_dec01.dat 5 1 point r . 10 AZ header hetAZindo_dec01.dat 5 2 point g . 10 AZ DEC hetAZindo_dec01.dat 5 3 pointopen b o 30 HETQ stru hetAZindo_dec01.dat 5 4 pointopen m h 10 HETQ DEC NOTICE: I use a new point type = pointopen [sco@mcs T1]$ xyplotter List.1 List.axes final plot was made with: [sco@mcs T1]$ pxy_SM_plot.py STYLE -12 100 0 360 SHOW This plot took just a few seconds to display.