Exporting Postscript from Lemur

Frequency Graph

A two dimensional picture which replicates the standard Lemur display. Time is on the X-axis and frequency is on the Y-axis. Magnitude is shown with varying shades of gray and/or varying line thicknesses.

Magnitude Graph

A three dimensional picture with time on the X-axis, frequency on the Y-axis, and magnitude on the Z-axis. To avoid confusion about whether the magnitude or frequency is changing, the frequency displayed for each track is the average frequency over the track's duration.

To generate postscript, open a Lemur file and select Export from the File menu. Choose Postscript File from the list of file types to export.

You will be presented with a dialog box with a variety of export options:

• First and Last Frame - use these to "zoom in" on a specific range of frames you would like to include in the Postscript graph. Only frames in the specified range will appear in the postscript file.
• Minimum and Maximum Frequency - use these to "zoom in" on a specific range of frequencies you would like to include in the Postscript graph. Only frequencies in the specified range will appear in the Postscript file.
• Precision - the number of frames to skip between each set of Postscript data points. For instance, a precision of 10 would only create postscript data points every 10 frames. This number is used to reduce the size of the postscript file, and consequently the time required to print the file. If you are looking for a quick, rough picture of your analysis, you can fill in a fairly large number. If you are creating postscript graphs for publication, you may want to fill in a smaller value and wait for the larger postscript files to print.
• Magnitude or Frequency Graph - select the type of graph you would like to export. There are several fields which are specific to each type of graph:

  Magnitude Graph

  press the Decibels button to use a decibel scale. The default is to use a linear scale with 0.0 as the minimum magnitude and 1.0 as the maximum magnitude. The Z-axis of the graph will only continue up to the highest magnitude peak which occurs in the Lemur file.

  Frequency Graph

  There are two ways to indicate magnitude information in a frequency graph:

  1. Gray range -- Enter a number between 0.0 and 1.0 which indicates the fraction of the grays available that you would like to use to display magnitude information:
     • 0.0 - only black is used.
     • 0.5 - only the darkest 50% of the grays available are used.
     • 1.0 - the entire range of grays is used.

     The drawback of entering 1.0 is that some tracks will be displayed using an extremely light shade of gray which may be difficult to see.

  2. Line thickness -- both the minimum and maximum thicknesses of the lines used to represent tracks can be specified. If the minimum and maximum thicknesses are equal, line thickness is not used to display magnitude information.

The default values will create a frequency Postscript graph of the entire file which uses shades of gray to indicate magnitude information. It should closely resemble the initial view of the file as it appears when it is first opened in Lemur.