Software for Stationary Scales

[pheon]

Does anyone know of software for producing stationary scales, i.e. nomographs of functions of just two variables?

[RonDoerfler]

Just so you know that your post isn't being ignored, I did try to find something available online that would work but I wasn't able to find anything. You're talking about a simple scale like that shown in the upper corner of this blog, right? I tried to make PyNomo plot one by doing the "general" type of nomogram and having two of the scales reside at x=0, but Leif is too smart for me and the code complains about a "singular matrix." I tried doing the same thing to an interactive online software tool at http://www.ece.rochester.edu/~jones/NomoDevel/index.htm but I couldn't fake that out, either. You would think that there would be some software somewhere that could create such a scale.

Ron

[Leif]

Dear pheon (and Rob)

I try to make simple code example to build a double scale by using pynomo...

\leif

[Leif]

Here is code to produce Fahrenheit-Celcius conversion by using PyNomo 0.1.0b1. See http://pynomo.org. The language is python.
I have corrected bugs and changed syntax in the class Nomo_Axis in the future version of PyNomo. It will take still my
limited time to have it out.

Code: Select all

from nomo_axis import *

F_start=-40.0
F_stop=90.0
C_start=-40.0
C_stop=30.0

def celcius(fahrenheit):
    return (fahrenheit-32.0)/1.8

c = canvas.canvas()
# define Fahrenheit scale
Nomo_Axis(func_f=lambda x:0,func_g=lambda y:celcius(y)*0.2,start=F_start,stop=F_stop,
              turn=-1,title=r'$^\circ$ F',canvas=c,title_x_shift=-1.0)
# define Celsius scale
Nomo_Axis(func_f=lambda x:0,func_g=lambda y:y*0.2,start=C_start,stop=C_stop,
              turn=1,title=r'$^\circ$ C',canvas=c,title_x_shift=0.5)
# write pdf-file
c.writePDFfile("double_test.pdf")


So no warranty... hope it works.

\leif

[pheon]

I tried the code but got this error

$ /opt/local/bin/python2.4 test.py Traceback (most recent call last):
File "test.py", line 1, in ?
from nomo_axis import *
ImportError: No module named nomo_axis

I assume I haven't installed something correctly. I followed the pynomo instructions and can run the examples OK.

[Leif]

$ /opt/local/bin/python2.4 test.py Traceback (most recent call last):
File "test.py", line 1, in ?
from nomo_axis import *
ImportError: No module named nomo_axis

If you installed PyNomo using command (or using windows .exe)

Code: Select all

python setup.py install

you should have pynomo in your path and this command should find.

Python tries to load file nomo_axis.py with the command

Code: Select all

from nomo_axis import *

and cannot for some reason find it.

\leif

[RonDoerfler]

I had the same problem as pheon, but after I re-installed Pynomo (via the Windows executable) everything worked fine. It looks great--thanks, Leif!

Ron

[Leif]

Sorry for inconvience, but there was a mistake in the code above in package loading definitions.
The code above works only if it resides in same directory as nomo_axis.py. Below is corrected code that
works.

Code: Select all

from pynomo.nomo_axis import *
from pyx import *

F_start=-40.0
F_stop=90.0
C_start=-40.0
C_stop=30.0

def celcius(fahrenheit):
    return (fahrenheit-32.0)/1.8

c = canvas.canvas()
# define Fahrenheit scale
Nomo_Axis(func_f=lambda x:0,func_g=lambda y:celcius(y)*0.2,start=F_start,stop=F_stop,
              turn=-1,title=r'$^\circ$ F',canvas=c,title_x_shift=-1.0)
# define Celsius scale
Nomo_Axis(func_f=lambda x:0,func_g=lambda y:y*0.2,start=C_start,stop=C_stop,
              turn=1,title=r'$^\circ$ C',canvas=c,title_x_shift=0.5)
# write pdf-file
c.writePDFfile("double_test.pdf")

One day there will be PyNomo documentation and more examples... I should integrate grid elements to build overall nomograms with 3+ variables. With this done, I think there is enough features for next distribution.

\leif

[RonDoerfler]

I had downloaded nomo_axis.py separately and put it in the same directory when I was trying different things to get it to work, so that's probably why it worked for me.

Thanks, Leif.

Ron

[pheon]

After reading about Python a bit, I got it to work by changing the first line to

from pynomo.nomo_axis import *