[DaveyCIS]

Hi all,

I am currently in my fourth year of my bachelors degree in Computer Science and about to dive head first into my Individual Project. The project is aimed at Mining and Visualisation of Big Data.

The data I will be mining and visualising is NMR Spectra (I think I have said that right), I have a data set with a LOT of different values however, in an X/Y Axis on a graph I do not know the Units of measurement and would be very appreciative of any help given to clear up the many gaps in my understanding.

David

[Irlanur]

usually the x axis denotes the chemical shift in ppm (it just a frequency difference divided by a reference frequency), the y axis is usually not even denoted. would be some kind of Voltage, depending on how you process the data.

But I suppose you work with some kind of multidimensional NMR?

[DaveyCIS]

Hi Irlanur thank you for your quick reply!

Ok so ppm being parts per million or alternatively mg/L, say in a range from 10 to -1. If the visualisation is in a form of a line graph, what dictates the height of the vertices if the coordinates are not in the form of a vector but just a float value.

David

[Irlanur]

mg/L

haha definately not, no. It's ok, you're a computer scientist;)

in a range from 10 to -1

that's good for 1H-NMR

If the visualisation is in a form of a line graph, what dictates the height of the vertices if the coordinates are not in the form of a vector but just a float value.

doenst make any sense. I suppose you know the x-range and number of points, so the data you have might only be the y-value.

what's the project about anyway? i mean it's not that chemists couldn't visualize NMR spectra...

[DaveyCIS]

Ah ok, so definitely not mg/L that is fine.

The values are definitely for the x-axis, I've discovered that I have to infer the Y values from the quantity of x values within same positions to gauge the relative intensity of the chemicals ions/molecules.

Ergo the Y axis is 'relative intensity' or 'signal intensity of area', would you agree with this?

I can't divulge much about the project unfortunately however I can say that it is not simply the visualisation of NMR Spectra. :-)

Thank you again,
David

[kriggy]

Just to clarify:
chemical shift (x axis) is frequency at which the given nuclei resonates. It is relative number since there are many different NMR mashines and if you have different operating frequency of the NMR then nuclei resonate at different frequencies and you cannot compare spectra from different NMR mashines (ie. 300MHz vs 400MHz etc..)
Its calculated this way:
= (resonance freq. of given nuclei - resonance freq.of standard) / frequency at which the NMR operates

http://en.wikipedia.org/wiki/Chemical_shift

ad y axis: yea I agree its signal intensity