XPMS2D User's Guide

Version 3.0.3

Table Of Contents

1. Overview
2. Getting Started
   1. Acquiring
   2. Installing
   3. Environment
   4. Fonts
   5. Command line options
3. Probe Selection Window
   1. Entering start time
   2. Selecting and Deselecting Probes
   3. Paging through data
4. Plot Canvas
   1. Guide to menus
      1. File menu
      2. View Menu
      3. Options Menu
5. Known problems

Overview

The primary file format supported is here https:://www.eol.ucar.edu/raf/software/OAPfiles.html. We use translators (pads2oap and translate2ds) to convert SPEC and DMT probe data to this format. These translators are available as part of the github repository listed below.

xpms2d was written at the Research Aviation Facility of The National Center for Atmospheric Research to view and perform quality control of our PMS-2D data. Every effort has been made to make it "what you see is what you get" between the screen and printouts.

Getting Started

Acquiring

xpms2d is available at https://github.com/ncar/aircraft_oap. Check out with 'git clone --recursive https://github.com/ncar/aircraft_oap'.

Installing

For system use, the binary may be placed in something like /usr/local/bin.

For single user, place the binary in ~/bin (Make sure ~/bin is in your PATH).

Environment

xpms2d is written in C++, requiring X11/R6 and Motif 2.0 (or later). Specifically it was developed on Redhat Enterprise Linux, using the GNU compiler gcc. xpms2d has been successfully compiled on Mac OS X, this does require, XCode and XQuartz. See Makefile for more details.

xpms2d uses, though it is not required, a shell environment variable called DATA_DIR as the default directory to locate data files.

Command Line Options

data_file, a raw PMS-2D data file.

Examples

Run with no command line parameters:

1024% xpms2d

Load a single data file:

1025% xpms2d /home/data/162rf08.2d

Probe Selection Window

Figure 1. xpms2d Control Window.

Moving around the file

Entering start time

Enter the start time in the left text widget and press apply to advance to a specific time. The Time warp scale may be dragged to correspond to a certain point in the file.

Movie/Advancing

The Start and Stop buttons may be used to automatically advance frames of data, use the Frame delay scale for the desired amount of delay between page updates. Step Bkd and Step Fwd buttons may be used to advance forward and backwards when the movie is stopped.

Selecting and Deselecting Probes

Click button(s) for probes you wish to view.

Sync and timing word legend:

• Green = accepted
• Yellow = zero area image/rejected
• Red = rejected
• Blue = Overload word, Fast2D only.
• Black = not detected by software

Figure 2. Sample data from xpms2d of traditional 32 diode 2d data.

Figure 3. Sample data from xpms2d of new 64 diode Fast2D data.

First line of text

• Time stamp is stamped at the moment the data sytem is interrupted to download the data (End of Record).
• TAS = True Air Speed.
• overLoad = The length of time the probe was shut down while downloading this record (shouldn't exceed 86 millseconds [red] for RAF data) in milliseconds.
• nParticles = The number if particles detected by the software in the record.

• elapsed time = The difference between this time stamp and the previous one. This delta data system time, in seconds.
• timeBarTotal = The summation of all the timing words in the record, in seconds.

• 1st % = % over- or underlap of timing words compared to data system time stamps (timeBarTotal / elapsed time).
• 2nd % = % over- or underlap of timing words plus the overLoad compared to data system time stamps (timeBarTotal+overLoad / elapsed time). 100.0% is a perfect value.

Second line of text

• sv = Sample Volume (see Figure 3).
• area = Sum of all shadowed pixels.
• conc = Total concentration as determined by selected method.
• lw = Liquid water content.
• z = Reflectivity.

Method

Basic

Actual sample volume which passed through the probe, with no additional rejection other than listed below. Particle size is the greater of ix and iy. ix is along the flight path.

Entire-in

This emulates the 260X. Any particle which touches an end diode is rejected. Particle height (iy) is used for sizing.

Center-in

Any particle who's center is within the diode array is kept, with the size being the greater of ix and iy. This is used in our size distribution algorithm and a good all around choice.

Reconstruction

Particles where iy is at least 20% of ix are kept.

Basic rejection criteria for all methods above:

• Zero-area-images are rejected.
• Stuck bit rejection, where iy equals 1 and ix is greater than 3. ix is along the flight path.
• Area ratio rejection is applied. That is total number of shadowed pixels divided by computed area based on diameter (max x, y).

Green = Reconstruction, Blue = Center-in, Red = Entire-in

Figure 3. 2D sample volumes for 32 diode probes.

Algorithms are outlined in:

Heymsfield, A. J., Parrish, J. L., 1978: A Computational Technique for Increasing the Effective Sampling Volume of the PMS Two-Dimensional Particle Size Spectrometer. J. Appl. Meteor., 17, 1566-1572

Density

Reject Ratio

Canvas Features

Magnify

Guide to Menus

File Menu

The items in the File menu allow opening of data files from disk, printer setup, and printing. In the case of an operation that will overwrite an existing file, you will be prompted by an alert that allows you to abort the write if you don't want the file to be overwritten.

Open Data File

This displays a File Selection Box to select a file to read. There is no error checking to see if the input file is valid. Invalid files tend to cause a segmentation fault. If this is the first time you have opened this file, xpms2d will create an index file; this may take a minute or more.

Save PostScript

This displays a File Selection Box prompting for the name of the file where you want to write the PostScript output.

Printer Setup

This pops up a window with options to change the 'lp' command, the size of plot to be printed, whether to print landscape or portrait, and color vs. black and white.

Print

This opens a pipe and sends PostScript commands to lp(1).

Save PNG

This option allows you to save the plot image as a graphics file, which can then be used in web pages, etc. You can adjust the size of the image saved by first sizing the plot canvas.

Known Problems

• Using the window manager X to close or dismiss a window will cause a core dump. Use 'Dimiss' buttons.
• If the menu and button text shows up as squares, then some fonts are missing. 'yum install "xorg-x11-fonts-ISO8859-1*"' should solve the problem.
• Invalid data files may cause a core dump.

Author