How to plot geo-data using matplotlib/python?

How can we plot a FOUR WAY LOGARITHMIC GRAPH using Excel or MATLAB or any common application?

• I am working on structural dynamics. In a textbook, i came across acceleration, velocity and displacement spectra plotted on the same graph with X axis as the Time Period axis. The Y axis is, say, displacement. Then the other two i.e. velocity and acceleration are plotted in the shape of a cross; inclined at +45 and -45 degrees with the x-axis. And the plots are logarithmic. Any idea how to plot this kind of graph using any common application such as Excel or MATLAB, or any good freeware from the internet??

• Answer:

  If I understand your question correctly, I have seen this kind of representation in the Shock and Vibration Handbook, representing the log displacement, velocity and acceleration response of a resonant mode to excitation at various ratios of forcing to natural frequency (wf/wn). A similar plot is shown in the reference. Contrary to answer 1's judgment, this is a very clear and compact way to show the data, because a single response curve (or a family of such curves portraying responses with various amounts of damping) serves to display all 3 dependent variables. Velocity gridlines are horizontal. Since in free vibration displacement=velocity*wn and acceleration=velocity/wn, displacement gridlines are tilted at 45 degrees from the x axis, and acceleration gridlines are tilted at 135 degrees. I think you are asking how to generate these gridlines. For each gridline you need to join points at the left and right edges of the graph, which are simply projections of two constants. E.g., say you're dealing with acceleration, the grid-line you are drawing represents an acceleration of 0.1, and log (frequency ratio) ranges from -2 to 2. Then the data for your points are log(-2), log(0.1)+2 on the left and log(2), log(0.1)-2 on the right. Follow the same logic for the other gridlines. This can be done by manual programming in either matlab or excel and automatically by specialized plot programs, one of which is for sale on the ref. page.