The question is simple but the answer can be quite involved.

First of all the choice of a tool will depend on the kind of data

to be plotted. One of the main factors is the dimension of the

domain over which the data is plotted -- 1D (for instance function

of one variable) versus 2D and 3D (fields defined over

two or three dimensional regions). Another issue is if you deal

with static or time dependent data.

Also the term "user friendly" can be understood in different ways.

Most of the time it will be understood in the sense that the tool

provides a GUI, where you can make some clicks and get the results.

That might be the case for some users but for me the indicator

of "friendliness" is the level of automation I can get from the

tool. If I have a single data set and I am going to prepare only

one version of the plot then GUI tools are OK. However if I have

hundreds of data sets and I would like to use visualisation to

understand the data then often it turns out that "the GUI way"

is hard to be automated. Thus I would not dismiss command line

tools because they seem archaic or difficult to use. In the long

term investment in them will be very beneficial.

As for a more concrete answer I would say:

gnuplot (http://www.gnuplot.info) for traditional graphs

ParaView http://www.paraview.org/ and other VTK based tools for

visualisation of multidimensional

fields ( e.g. tensor ones) over complex 2D or 3D domains (also

for time dependant data).

Hi

This is very well known question. Also the answer is simple: there is no free software for this. The only one, not free, exists; it is the combination of Origin (for plotting) and Matlab (to calculate and prepare data sets). Everybody has suffer this someday. I have done, long time ago.

Sorry for disappointment.

Hey Stanislav Kolpakov .... thnx for ur feed back.. and support..

yes... we hope in future we may get an alternate to such type of tools

Thank u Roman, for ur kind and informative feed back...

Graph pad (Prism) can be the best option.