GOES Stuff
GOES SPACE ENVIRONMENT MONITOR CD-ROM
1-Minute & 5-Minute Averages
January 1986 - April 1994
User Documentation
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June 14, 1994
National Oceanic and Atmospheric Administration
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National Geophysical Data Center
Solar-Terrestrial Physics Division
Dan Wilkinson
dcw@farpoint.ngdc.
(303) 497-6137
Greg Ushomirskiy
greg@farpoint.ngdc.
(303) 497-5931
NOAA E/GC2
325 Broadway
Boulder, CO 80303
TABLE OF CONTENTS
TABLE OF CONTENTS 1
INTRODUCTION 3
DATA WARNINGS 3
X-Rays 3
Energetic Particles 3
Magnetometer 4
HEPAD 4
Data Gaps 4
LATE BREAKING UPDATES OR ERRATA 5
SYSTEM REQUIREMENTS 5
DIRECTORY STRUCTURE 5
FILE NAMING 5
DATA FORMAT 5
DATA PACKING 7
DATA FLAGS 8
SMS/GOES SATELLITE SYSTEM 8
MAGNETOMETER 8
X-RAY SENSOR (XRS) 8
ENERGETIC PARTICLE SENSOR (EPS) 8
HIGH ENERGY PROTON AND ALPHA-PARTICLE DETECTOR (HEPAD) 9
GOES ENERGETIC PARTICLE CORRECTION ALGORITHM 9
DOS PLOTTING SOFTWARE 10
Installation 10
Quick-Look Example Session 10
Main Screen 11
File 11
Manual Select 11
Change Directory 11
Create List 11
Use List 11
Display 12
Setup 12
Exit 12
Graphics Screen 13
Legend 13
Zoom 13
Pan 13
Data Select 13
Shading 13
Black & White 14
Data Capture 14
Screen Capture 14
Exit Graphics 14
DOS UTILITIES 14
DOS Printing Software 14
DOS Binary to ASCII Software 14
IDL PLOTTING SOFTWARE 14
Installation 15
Unix 15
Microsoft Windows 15
Macintosh 16
Basic Operation 17
Sample Program Session 17
Selecting Data Components and Plot Intervals 17
Overview of Controls 18
Menu Structure 18
Description of Controls 18
Plot Area 18
Tools 19
Plot Legend 19
Data Values 19
Annotate Plot 19
Printer Setup 20
Save Image 20
System-Specific Notes 21
Unix 21
Microsoft Windows 21
Macintosh 21
Troubleshooting 21
INTRODUCTION
This CD-ROM of GOES Space Environment Monitor data is the second such CD to be published by the National Geophysical Data Center. It contains 5-minute and 1-minute averages of the X-ray, energetic particle, and magnetic field data collected by GOES-5, -6, and -7 between January 1986 and April 1994. Software is supplied for displaying the data. This edition of the GOES CD-ROM improves on the previous in several ways:
1. Data coverage was expanded from January 1986 - June 1992 to January 1986 - April 1994. We hoped to extend the coverage back to January 1983; however, many things undermined those plans, not the least of which was the launch of GOES-8.
2. New display software has been added for users of Interactive Data Language (IDL) from Research Systems, Inc., Boulder, Colorado. The software has been tested under UNIX, MS Windows, and Macintosh. The original DOS software is still included.
3. Some data gaps found in the original CD-ROM have been filled.
4. The HEPAD data from 1986 to 1992 have been quality checked and corrected.
5. All reported errata in the documentation and software have been fixed.
The next GOES CD-ROM will extend the data back to 1983 as well as forward to encompass the latest data. We anticipate that a new data format will be incorporated on the next CD-ROM to make more efficient use of the CD’s capacity.
DATA WARNINGS
The volume of these data makes it impossible to issue a guarantee as to the quality of each and every data point. A quality pass has been made though each file to identify values that make wild excursions from the norm, and instances of such have been looked at on a case by case basis and compared with concurrent data from other satellites. Data identified as bad have been replaced with the bad data flag. Users should be suspicious of ‘spikes’ in the data and attempt to correlate them with other sources before assuming that they represent the space environment.
The time of these observations has not been corrected for the down-link and preprocessing delays. The Space Environment Laboratory has not made an accurate determination of this delay, but they say it is consistent and within the range of 1 - 5 seconds.
X-Rays
The X-ray sensors may experience significant bremsstrahlung contamination. This contamination is caused by energetic particles in the outer radiation belts and depends on satellite local time, time of year, and the local particle pitch-angle distribution. The X-ray sensors are also sensitive to background contamination due to energetic electrons that either deposit their energy directly in the telescope or strike the external structure and produce bremsstrahlung X-rays inside the ion chamber. Comparison of X-ray measurements from two concurrently operating GOES satellites reveals a systematic difference signal that shows both diurnal and seasonal variations. These variations are most noticeable when solar activity is low to moderate.
Energetic Particles
Users of GOES particle data should be aware that significant secondary responses may exist in the particle data, i.e. responses from other particles and energies and from directions outside the nominal detector entrance aperture. The energetic protons in 5-minute files whose names begin with I or Z have been partially corrected for these effects. A description of the algorithm is included in this document.
The Electron detector responds significantly to protons above 32 MeV; therefore, electron data are contaminated when a proton event is in progress. We are considering scanning the archive for particle events and replacing the corresponding electron data with the bad data flag.
The GOES-5 electron channel is noisy from 1986 onwards and readings are a possible factor of 2 high.
One component of the GOES-6 particle detector system has had radiation damage since 1986 that reduced its counting efficiency progressively. At present the E1 and P4 channels derived from this component record at only a few percent of their proper rates.
In 1991 the telescope component of the GOES-7 energetic particle detector system experienced episodes of malfunction (noise). The first period began at 0330 UT, October 18, 1991 and extended to November 5, 1991. The detector was commanded off for 12 hours. At turn-on the detector appeared to have recovered, but failed again on November 11, with a rerecovery on November 12 after a second turn-off of three hours. The detector has since operated normally. The noise periods may be identified by unusually high rates being shown by the P1 channel and the derived > 1 MeV integral channel.
Currently, the GOES-7 Energetic Particle Sensor is left turned off for 4 hours after eclipse to minimize bad data.
Magnetometer
The GOES-5 magnetometer HP component had an artificial offset from January 2, 1986 to March 13, 1986. The data are left as is.
The GOES-6 magnetometer experienced irregularities in the magnetometer on September 9, 1991. The transverse component, which is deconvoluted into the HE and HN components (orthogonal to spin axis), began to yield bad values due most likely to an error in locating Earth’s limb. The problem persists to this time. Although the possibility exists that a proper deconvolution may be arrived at, the data for these values on this CD-ROM have been replaced with the bad data flag. In summary, the HE and HN components of the GOES-6 magnetometer have been filled with the bad data flag from September 9, 1991 onwards. The HP component is left intact.
The GOES-7 magnetometer experienced instrument failure of its transverse component in May 1993. Only the HP component is available from May 1993 onwards. The HN and HE components are filled with the bad data flag.
The absolute accuracy of HP (spin axis component) on all GOES can be uncertain because of difficulties in calibration.
HEPAD
The HEPAD data through December 1992 have had corrections applied and give a better representation of the high energy particle environment than the previously published version. Because of very large spurious points in the original data, the maximum data value in each sampling interval has been ignored in the corrected data. Data after December 1992 have not had these corrections applied.
The user may improve the P8 and P9 count rates by applying the following to correct for backwards particles:
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Data Gaps
GOES-6 1-minute data from June 5, 1988 to August 14, 1988 are missing particle and magnetometer components.
GOES-6 5-minute data from June 5, 1988 to July 31, 1988 are missing particle and magnetometer components.
LATE BREAKING UPDATES OR ERRATA
To access the latest versions of software or to learn of bugs in software or errata in data you may access host ftp.ngdc. as user anonymous and download file update.txt from directory STP/GOES/AVERAGED/CDROM94. If you do not have network access, call the number on the title page.
SYSTEM REQUIREMENTS
To read this CD-ROM, a CD drive capable of reading data in the ISO 9660 format is required. This is the most common standard and is supported on virtually all platforms.
DIRECTORY STRUCTURE
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File Naming
DSSRYYMM.BIN
|D |Data version: |
| |G X-ray, Mag., Electrons & Uncorrected Proton Channels |
| |Z X-ray, Mag., Electrons & Corrected Proton Channels |
| |I X-ray, Mag., Electrons & Corrected Integral Proton |
| |H X-ray, Mag., Electrons & HEPAD |
| |A X-ray, Mag., Electrons & Uncorrected Alpha-Particles |
|SS |Satellite ID, i.e., 07 = GOES-7, etc. |
|R |Time resolution, i.e., 5 = 5-minute averages, 1 = 1-minute averages |
|YY |Year |
|MM |Month |
For example, G0759201.BIN is the file name used for GOES-7 5-minute data for January 1992.
DATA FORMAT
The data files are written as a table of records. Each record is made up of 18 2-byte (16-bit) ‘little-endian’ binary integer words - the least significant byte is followed by the most significant byte. The following table lists how this compares to some popular systems. If your computer does not default to ‘little-endian’ format, you will have to swap bytes accordingly.
Integer Byte Order
|System |16-BIT |32-BIT |
|GOES 5-min and 1-min avgs |B0 B1 | |
|INTEL |B0 B1 |B0 B1 B2 B3 |
|IBM PC |B0 B1 |B0 B1 B2 B3 |
|VAX |B0 B1 |B0 B1 B2 B3 |
|DEC STATION |B0 B1 |B0 B1 B2 B3 |
|PDP |B0 B1 |B2 B3 B0 B1 |
|FITS |B1 B0 |B3 B2 B1 B0 |
|MOTOROLA |B1 B0 |B3 B2 B1 B0 |
|DATA GENERAL |B1 B0 |B3 B2 B1 B0 |
|MACINTOSH |B1 B0 |B3 B2 B1 B0 |
|APOLLO |B1 B0 |B3 B2 B1 B0 |
|SUN-SPARC |B1 B0 |B3 B2 B1 B0 |
|IBM 360/370 |B1 B0 |B3 B2 B1 B0 |
Header Record
|Word |Description |
|1 |Satellite ID (6=GOES-6, 7=GOES-7, etc.) |
|2 |Year (88 = 1988) |
|3 |Data Type: |
| |102 X-ray, Mag., Electrons & Uncorrected Proton Channels |
| |103 X-ray, Mag., Electrons & Corrected Proton Channels |
| |104 X-ray, Mag., Electrons & Corrected Integral Protons |
| |105 X-ray, Mag., Electrons & Uncorrected Alpha-Particles |
| |106 X-ray, Mag., Electrons & HEPAD |
|4 |Average Type (1 or 5 for 1-min or 5-min) |
|5 |Month |
|6-18 |Unused (zeros) |
Data Record
|Word |Description |
|1 |Status Word #1 |
|2 |Status Word #2 |
|3 |Day of Year |
|4 |Minute of Day |
|5 |XL 1 - 8 Å X-rays |
|6 |XS 0.5 - 4 Å X-rays |
|7 |HP Parallel to satellite spin axis |
|8 |HE Earthward |
|9 |HN Normal to HP and HE, points West for GOES 1-4, East for GOES 5+ |
|10 |Htot Magnitude of total magnetic field vector |
|11 |E1 > 2 MeV (Electrons/cm2 sec sr) |
Data Version: 'G' or 'Z' (see File Naming)
|Word |Description |
|12 |P1 0.6 - 4.2 MeV (Protons/cm2 sec sr MeV) |
|13 |P2 4.2 - 8.7 MeV (Protons/cm2 sec sr MeV) |
|14 |P3 8.7 - 14.5 MeV (Protons/cm2 sec sr MeV) |
|15 |P4 15.0 - 44.0 MeV (Protons/cm2 sec sr MeV) |
|16 |P5 39.0 - 82.0 MeV (Protons/cm2 sec sr MeV) |
|17 |P6 84.0 - 200 MeV (Protons/cm2 sec sr MeV) |
|18 |P7 110.0 - 500.0 MeV (Protons/cm2 sec sr MeV) |
Data Version: 'I'
|Word |Description |
|12 |I1 > 1 MeV (Protons/cm2 sec sr) |
|13 |I2 > 5 MeV (Protons/cm2 sec sr) |
|14 |I3 > 10 MeV (Protons/cm2 sec sr) |
|15 |I4 > 30 MeV (Protons/cm2 sec sr) |
|16 |I5 > 50 MeV (Protons/cm2 sec sr) |
|17 |I6 > 60 MeV (Protons/cm2 sec sr) |
|18 |I7 > 100 MeV (Protons/cm2 sec sr) |
Data Version = 'A'
|Word |Description |
|12 |A1 3.8 - 9.9 MeV (Alpha-particles/cm2 sec sr MeV) |
|13 |A2 9.9 - 21.3 MeV (Alpha-particles/cm2 sec sr MeV) |
|14 |A3 21.3 - 61. MeV (Alpha-particles/cm2 sec sr MeV) |
|15 |A4 60.0 - 180 MeV (Alpha-particles/cm2 sec sr MeV) |
|16 |A5 160.0 - 260 MeV (Alpha-particles/cm2 sec sr MeV) |
|17 |A6 330.0 - 500 MeV (Alpha-particles/cm2 sec sr MeV) |
|18 |not used |
Data Version = 'H'
|Word |Description |
|12 |P8 370 - 480 MeV (Protons/cm2 sec sr MeV) |
|13 |P9 480 - 640 MeV (Protons/cm2 sec sr MeV) |
|14 |P10 640 - 850 MeV (Protons/cm2 sec sr MeV) |
|15 |P11 > 850 MeV (Protons/cm2 sec sr) |
|16 |A7 630 - 850 MeV (Alpha-particles/cm2 sec sr MeV) |
|17 |A8 > 850 MeV (Alpha-particles/cm2 sec sr) |
|18 |not used |
DATA PACKING
Magnetometer values are stored as [pic].
X-ray and particle fluxes are stored as [pic].
DATA FLAGS
Zero X-ray and energetic particle flux values are stored as 32700.
All bad data values are stored as 32711.
SMS/GOES Satellite System
The Synchronous Meteorological Satellites (SMS-1 and SMS-2) and the Geostationary Operational Environmental Satellites (GOES-1, GOES-2, etc.) all carry on board the Space Environment Monitor (SEM) instrument package. The SEM has provided magnetometer, energetic particle, and soft X-ray data continuously since July 1974. Two SMS/GOES usually operate simultaneously in Earth’s equatorial plane. They travel in geosynchronous orbit (6.67 Earth radii) and are generally located at or between 75o and 135 o West longitude. This trajectory allows the detectors an unobstructed view of the sun for all but the few dozen hours per year when the Earth eclipses the sun.
The data are transmitted via direct telemetry to the Space Environment Laboratory Data Acquisition and Display System (SELDADS) in Boulder, Colorado, and are available through the Solar-Terrestrial Physics Division of the National Geophysical Data Center, an organization in Boulder known internationally as World Data Center A for Solar-Terrestrial Physics.
Magnetometer
A twin-fluxgate spinning sensor allows Earth’s magnetic field to be described by three mutually perpendicular components: HP, HE and HN. HP is parallel to the satellite spin axis, which is itself perpendicular to the satellite’s orbital plane. HE lies parallel to the satellite-Earth center line and points earthward. HN is perpendicular to both HP and HE, and points westward for SMS-1, SMS-2, GOES-1, GOES-2, GOES-3, and GOES-4, and eastward for later spacecraft. HE and HN are deconvoluted from the transverse component HT. Field strength changes as small as 0.2 nanoTesla can be measured.
The magnetometer samples the field every 0.75 seconds. Four of these values constitute a frame and are sent to the ground station together. For data from GOES-3 or earlier spacecraft, the high and low values in the frame were thrown out and the remaining value closest to the previous frame’s value is recorded. For data from GOES-5 and later spacecraft the high and low values in the frame are thrown out and the average of the two remaining values is recorded. No record is kept of which of the four values are used in the archive.
X-ray Sensor (XRS)
Ion chamber detectors provide whole-sun X-ray fluxes for the 0.5-to-4 and 1-to-8 Å wavelength bands. These observations provide a sensitive means of detecting the start of solar flares. Two bands are measured to allow the hardness of the solar spectrum to be estimated.
X-ray photons pass through a collimator which defines the view aperture, followed by a thin metallic window which defines the low energy threshold, before entering the ion chamber. The XRS viewing direction is in the meridian of the spacecraft spin axis. Dynamic positioning of the XRS elevation provides for maintaining the sun in the swept field. The X-ray emission of the sun is determined once during each spin. The spin period is 0.6 seconds and the data for both bands are given in Watts/cm2 sec. The full archive has 3.06 second time resolution.
Energetic Particle Sensor (EPS)
Solid-state detectors with pulse-height discrimination measure proton, (-particle, and electron fluxes. The look direction of the EPS is perpendicular to the GOES spin axis which is approximately aligned with Earth’s rotation axis. Since the satellite spin period, 0.6 seconds, is much shorter than the accumulation times, the EPS provides a spin-averaged estimate of the local high-pitch-angle particle fluxes. The integral electron channel is given in units of count/cm2 sec sr while the other channels are given in count/cm2 sec sr MeV at the average energy.
Because GOES spacecraft travel in a geostationary orbit, the E1 and P1 channels are responding primarily to trapped outer-zone particles. The P2 channel may occasionally respond to trapped particles during magnetically disturbed conditions. The geomagnetic cutoff at geostationary orbit is typically of the order of a few MeV as indicated by the lack of trapped P2 response except as noted above. Therefore, the remaining proton and alpha particle channels measure fluxes originating outside the magnetosphere -- from the sun or the heart of the Galaxy.
High Energy Proton and Alpha-Particle Detector (HEPAD)
The HEPAD consists of a solid state / Cerenkov telescope and a photo-multiplier. An “alpha lamp” provides a reference pulse for calibrating the photo-multiplier in flight.
GOES Energetic Particle Correction Algorithm
R. D. Zwickl
NOAA Space Environment Laboratory
In January 1990, an upgraded algorithm for calculating the energetic-particle differential and integral proton flux from measurements made by the energetic particle monitors aboard the GOES-6 and -7 satellites became operational in the Space Environment Services Center (SESC) of NOAA’s Space Environment Laboratory (SEL). The following is a brief description of the rationale for the new algorithm and its basic features.
Why Did We Need a New Algorithm?
The energetic particle monitors are simple solid-state sensors, designed to handle large count rates without overwhelming the electronics. Since their launch these instruments have met their design goals and have never saturated, even during the largest events. However, because they were required to measure high rates, the detectors were built with passive shielding (no anti-coincidence). This has allowed particles to pass through the shielding from any direction and be counted as though they had entered through the front collimator.
During solar energetic-particle events the low-energy passbands would detect particles at exactly the same time as the high-energy passbands did, even though it was impossible for the lower-energy particles to be present at such early times. During quiet times, cosmic rays and their secondary particles produce a very high background in the GOES sensors, in contrast to their effect on more advanced sensors that use active shielding (>100 times the “nominal” background).
The initial algorithm, used until January 1990, did not take either of those effects into account. (NGDC has since applied the correction algorithm to the earlier data from 1986 to 1990.)
The Upgraded Algorithm
The count rate as measured by any one of the seven energetic particle proton channels on GOES-6 or -7 (identical systems) can be given by
[pic]
where CMeas is the actual measured count rate, CTrue is the true count rate, S is the count rate generated by particles entering through secondary energy passbands (i.e., those particles not passing through the collimator), and BG is the background count rate (produced primarily by cosmic rays). Simply stated, the new algorithm solves for CTrue as follows:
[pic]
The first step in the algorithm is to determine the background count rate for each of the seven channels. Since the background varies with time, a filter technique is used to find a new minimum value within the previous 10 days or use the previous value. This background value is then subtracted from CMeas.
It is then assumed that the energy spectrum of the energetic particles, from one energy channel to the next, can be represented by a simple power law in energy ([pic] ), and that the secondary energy passbands that were determined during calibration are responsible for all of the secondary count rate. The resulting set of equations can then be solved, starting with the highest energy channel and working toward lower energies. All seven energy channels must contain data or no values are calculated.
Finally, each set of 5-minute-averaged values is calculated independently of every other set of values. This allows the corrected values to be calculated continuously in an operational environment.
Corrected proton channel data can be found in files that start with ‘Z’. Corrected proton integrals can be found in files that start with ‘I’.
DOS PLOTTING SOFTWARE
Installation
1. Create a directory on your computer to contain the GOES software for DOS
MD GOES
2. Move into that directory
CD GOES
3. Place the GOES CD-ROM into the CD-ROM drive and copy the contents of the \DISPLAY directory on the CD to the \GOES directory that you just created on your computer. Also copy the utilities from \UTILS. This example assumes that the CD-ROM is drive L:
COPY L:\SOFTWARE \DOS\ DISPLAY \*.*
COPY L:\SOFTWARE \DOS\ UTILS \*.*
Quick-Look Example Session
The goal of this session is to display the GOES Space Environment Monitor data for October 19-25, 1989.
1. Move to the hard drive directory where you have installed the software:
CD \GOES
2. Start GOES plotting software:
GOES
3. Use cursor keys to highlight FILE and press [Enter]
4. Use cursor keys to highlight CHANGE DIRECTORY and press [Enter]
5. Enter directory path for the 1989 data:
L:\1989 (Replace L: with your CD-ROM drive letter.)
press [Enter]
6. Use cursor keys to highlight USE LIST and press [Enter]
7. Use cursor keys to highlight the line containing 10/89 GOES-7 ... I0758910.BIN and press [Enter]
8. Use cursor keys to highlight DISPLAY and press [Enter]
9. Select a time interval to display, Day 19 0000 UT to Day 25 2400 UT:
19 [Enter]
00 [Enter]
25 [Enter]
24 [Enter]
press [PgDn]
10. Display a menu of useful options:
press [F1]
11. To exit the program press [Esc] several times.
Main Screen
The main screen has four user selectable options, File, Display, Setup, and Exit shown at the top of the screen. Access them by using the cursor keys to highlight the choice followed by pressing the [Enter] key. The bottom of the screen displays information about your computers state such as the directory where the program was launched labeled as Old and the current directory labeled as Dir. In addition, the DOS version, memory available, video display type, and currently selected data file are shown.
File
Selecting File from the main menu will pop-up another menu bar with the options Use List, Create List, Change Directory, Manual Select.
Manual Select
The user can use this option to directly enter the path of a data file to open. This is not the recommended method, however. You will find that the three options below, when used in concert, offer a much more elegant means of accessing the data files.
Change Directory
In many cases, including using data on the CD, you will wish to access data that resides in a directory different from the one in which the program was launched. This option will let you change to the directory containing the data you wish to view. When using the GOES CD you need to change to the drive that contains the CD-ROM and the directory that contains a specific year of data, e.g., L:\1994. After changing directory in this manner, you will see the change reflected at the bottom of the screen next to Dir.
Create List
When accessing a data set with hundreds of files, each with a cryptic identifying name, it is useful for the software to present the user with a list of choices rather than demand a specific file name. Create List is the first step in presenting such a list. A list of all GOES data files in the current directory is created. The list is named GOES.LST and is written in the current directory. Since CDs cannot be written to, the GOES CD-ROMs are always prepared with list files in each directory. If, however, you have copied some files to a hard disk directory, use this option to create a new list for them. This option will open all files in the current directory and check for the GOES header structure. When a GOES file is found, the information in the header is used to create a table entry. The list file is a simple text file so feel free to take a look at it outside of the GOES program with the text editor of your choice.
Use List
This is the way you select a particular month of GOES data. It opens the list file in the current directory and displays its contents. The user may scroll through the list with the arrow keys. When the data file you wish to open is highlighted, press [Enter]. You will notice several choices for any particular month. You can choose between satellites, and between time resolutions of 1-minute or 5-minute averages. You can also choose between different versions of the energetic particle data. (See chapter titled GOES Energetic Particle Correction Algorithm)
Display
After selecting a data file, use this option to display the data graphically. Enter the starting and ending day and hour. Pressing the [PgDn] key will cause the screen to switch to a graphics mode and the selected data interval will be plotted on the screen.
Setup
Selecting Setup from the main menu allows the user to choose between VGA and EGA graphics support. Although the program will probe your computers video capabilities and make a judgment based on the results, this option allows you to override that judgment.
Exit
Selecting Exit from the main menu will exit the program. Pressing [Esc] twice will also exit the program. Before the program closes, it writes file GOES.INI to the Old directory. This file contains the video mode, data file, and the directory path to the data file. The next time the program is executed file GOES.INI will be opened and these settings will be used upon startup. If for some reason the path no longer exists, e.g., CD-ROM drive is turned off, you can delete GOES.INI before starting the program and it will not look for the missing drive.
[pic]
Figure 1. Sample graphics screen.
Graphics Screen
The graphics screen shows data in three panels (see Figure 1). The top panel is X-rays, energetic particles are in the middle panel, and magnetic field data are in the bottom panel. The day of the month is shown in the X-ray panel only. The time is shown along the bottom of the magnetic field panel and symbols in yellow and blue indicate satellite local noon and midnight. Several options are available from the graphics screen. Pressing the [F1] key will display a list of them (see Figure 2). You may terminate a plot process by pressing [Esc].
[pic]
Figure 2. Option Menu for Graphics Screen.
Legend
[pic]
Figure 3. Sample Legend.
At any time while viewing a graphics screen the user may press [L] to display a legend of the data (see Figure 3).
Zoom
Pressing [+] will double the plotted time interval and pressing [-] will reduce the time interval by half. For example, if you are viewing 1 day’s worth of data, pressing [+] would expand the display to include 2 days. Pressing [-] would display 12 hours of data.
Pan
If you wish to move the viewing interval to the right or left by one half the time interval, use the right and left arrow keys. To pan by an entire data interval hold down the [Ctrl] key while pressing the arrow keys.
Data Select
When the graphics screen is first created, all three data types are displayed. To display one data type using the entire screen you press [X] for X-rays, [P] for particles, or [M] for magnetic field. Pressing [A] will display all three together again. When displaying all three data panels, the magnetometer panel is very narrow and the three traces may become a bit tangled. Pressing [H] will plot only the primary component HP, pressing [H] again will plot all three.
Shading
If you like lots of color, press [S] to shade the data traces. Pressing [S] again will return to the non-shaded data traces.
Black & White
If you plan to capture a screen for printing on a black & white printer, first change to the black & white display mode by pressing [B]. Pressing [B] again will return to color mode. When viewing in the black & white mode you will find it useful to turn off data shading if it has been activated.
Data Capture
Pressing [W] will write the data values for the current display to an ASCII text file in the OLD directory -- the directory where the program was executed. After creating the file its automatically generated name will be displayed.
Screen Capture
Pressing [Ctrl][W] will capture the entire graphics screen to a PCX graphics file. After creating the file its name will be displayed. The PCX file is useful for printing plots or incorporating them into documents. A separate DOS utility, PRTPCX.EXE, is included for printing these files to HP LaserJet or IBM/Epson compatible printers. The best way to print these files is to import them into a Windows paint package or word processor and print them using the Windows drivers for your printer. This will give you more control over the output size and quality.
Exit Graphics
Leaving the graphics screen is as simple as pressing the [Esc] key. To leave the entire program press [Esc] twice more.
DOS UTILITIES
Directory \SOFTWARE\ DOS\ UTILS contains two single function programs.
DOS Printing Software
If you have a HP LaserJet or Epson/IBM compatible printer you may print PCX files captured from the graphics screen with a program called PRTPCX. Options are passed to the program from the command line. To see a list of the options execute PRTPCX with no arguments.
Examples: PRTPCX fn /L1 (print file fn to laser printer on port LPT1)
PRTPCX fn /M2 (print file fn to dot matrix printer on port LPT2)
DOS Binary to ASCII Software
The best way to translate the binary data files to ASCII is to use the [W] option from the GOES program. This allows you to translate only the interval of interest. To translate an entire file to ASCII use BIN2ASC.EXE. The source code is included for C programmers looking for some clues. To see a list of the options execute BIN2ASC with no arguments.
Example: BIN2ASC -all c:\g0759203.bin c:\ascii\g0759203.asc
(Translate all data types from c:\g0759203.bin to c:\ascii\g0759203.asc)
IDL PLOTTING SOFTWARE
GOES Archive Browser is an application that lets the user plot, print, and analyze the data from the GOES SEM archive. Archive Browser is written in IDL (Interactive Data Language) and is not a standalone program. It requires IDL to be installed on the system.
Archive Browser should work properly on any system supported by IDL. Archive Browser has been successfully tested with IDL 3.5.1 on SunOS 4.1.3 and IDL 3.5.1 on Microsoft Windows 3.1. Archive Browser also runs under IDL 3.5.1 for Macintosh, although this version of IDL is not stable enough to be considered practical. Archive Browser has not been tested under VMS, however, we expect it to work just fine.
Installation
Archive Browser comes in three versions, Unix, MS Windows, and Macintosh. Although the Unix, Windows, and Macintosh files are identical, three versions of “packaging” were created to accommodate naming limitations of the CD-ROM.
Unix
On Unix machines, IDL is usually installed in the /usr/local/lib/idl directory. Archive Browser files should be placed in /usr/local/lib/idl/lib/goes. This operation may require superuser privileges.
1. Locate the Unix “tar” file in software/idl/unix/ave_plot.tar on the CD-ROM
2. Change directory to /usr/local/lib/idl/lib
3. Create subdirectory goes and change to it
4. Execute tar xvf /CDROM/software/idl/unix/ave_plot.tar
5. Archive Browser is now installed
Archive Browser includes several routines from John Hopkins University Applied Physics Lab IDL library. If you already have the full library installed, you should delete the directory goes/jhuapl and its contents.
If you do not have superuser privileges, Archive Browser can be installed in your user account. Follow the instructions above to “un-tar” the file into your account. Then modify the IDL_PATH environment variable to add the location of Archive Browser files to IDL’s search path. For example, if Archive Browser was installed in /homes/john_doe/idl/goes and IDL is installed in /usr/local/lib/idl then you should set IDL_PATH environment variable with the command
setenv IDL_PATH +/homes/john_doe/idl/goes:+/usr/local/lib/idl/lib
Microsoft Windows
On Microsoft Windows machines, IDL is usually installed in the C:\IDL directory. In this case Archive Browser files should be placed in C:\IDL\LIB\GOES.
1. From Program Manager, select File/Run.
2. Enter L:\SOFTWARE\IDL\WINDOWS\SETUP (if your CD-ROM is not at drive letter L:, substitute it accordingly).
3. The Setup program will ask for a directory in which to place the files. Specify IDL’s LIB\GOES subdirectory directory.
4. The Setup program will install the Archive Browser files in the appropriate places and exit.
5. Make sure the TMP environment variable is set in your AUTOEXEC.BAT file and it points to a directory with at least 1 MB of free space. Your AUTOEXEC.BAT file should contain a command similar to SET TMP=C:\TMP.
Archive Browser includes several routines from John Hopkins University Applied Physics Lab IDL library. If you already have the full library installed, you should delete the directory GOES\JHUAPL and its contents.
If you do not have write privileges in the IDL directory (e.g., if IDL is installed in a shared directory on a Novell server), you can install Archive Browser in a directory on a local hard disk. In this case you need to add that directory to the IDL search path. For example, if you installed Archive Browser in C:\GOES and IDL is installed in M:\PUBLIC\IDL, to modify IDL_PATH variable start IDL, select File/Preferences/Path, and enter +M:\PUBLIC\IDL\LIB;+C:\GOES.
Macintosh
Macintosh version of the Archive Browser is located in SOFTWARE:IDL:MAC:AVE_PLOT.HQX on the CD-ROM. It is a self-extracting archive converted into BinHex form for safe transportation on a non-Macintosh CD-ROM. To install Archive Browser you need a utility that can un-BinHex files (such as Stuff-It Expander available on a variety of bulletin boards and FTP sites). After expanding the self-extracting archive, place the resulting folder named GOES inside the lib folder of IDL.
[pic]
Figure 4. Typical Archive Browser Screen.
Archive Browser includes several routines from John Hopkins University Applied Physics Lab IDL library. If you already have the full library installed, you should delete the JHU/APL folder that is located inside the GOES folder.
If you do not have write privileges in the IDL directory (e.g., if IDL is installed in a shared directory on an AppleShare server), you can install Archive Browser in a directory on a local hard disk. In this case you need to add that directory to the IDL search path. Use the Search Path command from the Edit menu to tell IDL where to look for the Archive Browser files. Make sure to check the Search Subfolders box.
Basic Operation
To run Archive Browser start IDL, and execute AVE_PLOT. After a short delay, the main program window will appear (see Figure 4).
The Archive Browser screen consists of two parts, a menu section and a plot window. Controls in the menu section are used for selecting data to be displayed in the plot window, printing or saving the contents of the plot window, and miscellaneous utilities.
Sample Program Session
1. Start IDL and execute AVE_PLOT from the IDL prompt.
2. Press the File button on the menu bar. Select a GOES file from the list. In a moment, a plot of the first hour of data will appear.
3. Press 1 Month button to plot a whole month of data.
4. Uncheck Display: X-Ray button and press Plot. Only Particle and Magnetometer data will be displayed.
5. Press the Tools button. A pull-down menu will appear. Select Show Legend.. from the menu. A legend window will appear.
6. Press the Print button, then select OK in the Print To.. window. A hardcopy of the plot will be generated and sent to your printer.
7. Press Exit to end the program and return to the IDL prompt.
Selecting Data Components and Plot Intervals
Display section of the menu area contains X-Ray, Particle, and Magnetometer buttons that allow flexible selection of the data components to be plotted. By default, all three buttons are checked, which means that X-Ray, Particle (uncorrected, corrected, or integrated protons, (-particles, or HEPAD), and Magnetometer data are displayed. Any one or combination of two buttons can be unchecked to inhibit plotting of the corresponding data components. To display the current selection of data components press the Plot button.
Archive Browser provides three ways to select the time interval of the data. The smallest interval that can be displayed is one hour, the largest is one month. The current interval is always displayed in the From: Day/Hour To: Day/Hour section of the program window. Day and Hour fields can be edited directly to set the plot interval. After the desired interval is entered, press the Plot button to display it. The row of buttons next to the From: Day/Hour To: Day/Hour section of the program window can be used to modify the current interval. The 1 Hour button always selects an interval that begins with the From: Day/Hour time and ends one hour later. The 1 Day button selects a one day interval that starts with the From: Day/Hour time. The 1 Month button plots the whole month of data. Finally, 2x Interval and ½x Interval buttons double or halve the current interval, again starting with the From: Day/Hour time. Unlike editing the starting and ending times directly, interval selection buttons replot the data automatically (i.e. the Plot button need not be pressed). Finally, the starting time of the plot interval can be adjusted by dragging the slider right below the interval selection controls. If the interval is adjusted with the slider, the Plot button needs to be pressed to activate the changes.
Overview of Controls
Menu Structure
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Figure 5. Archive Browser Menu Structure.
Archive Browser menu structure is shown in Figure 5.
Description of Controls
Archive Browser controls are used to select plot interval, data components, and to manipulate appearance of the plot.
• Exit Exit the program and return to the IDL prompt.
• File Display the file selection dialog and open a GOES SEM file.
• Plot Replot the data with the currently selected plot interval and data components.
• Print Display a Print To.. dialog to set print options and create a hardcopy of the plot.
• Tools/Show Legend.. Display the plot legend in a separate window.
• Tools/Show Values.. Display data values in a separate window.
• Tools/Annotate Plot.. Display the plot annotation tool.
• Tools/Setup Printer.. Display Setup Printer dialog to set the printing options without producing a hardcopy of the plot.
• Tools/Save Image.. Display Save Image.. dialog to save the contents of the plot window to an image file.
• Help/How To Use.. Display simple operating instructions.
• Help/GOES Satellites.. Display a short description of GOES satellites and the SEM package.
• Help/About.. Display information about the authors of the program.
Plot Area
The plot area of the Archive Browser window contains plots of up to three components of the data in the currently selected file. The units are shown to the left of the plot panels, and the color legend can be displayed by selecting Tools/Show Legend.. Note that X-Ray and Particle plots are logarithmic, while the Magnetometer scale is linear. Vertical axis ranges cannot be changed in this release of the program.
The title of the plot shows the satellite id (e.g., GOES-7), data resolution (1- or 5-minute), the month of the plot, and the longitude of the satellite at the beginning of the time interval displayed in the window. Blue triangular marks on the top horizontal axis indicate local midnight, red marks indicate local noon.
Tools
[pic]
Figure 6. Plot Legend Window.
Plot Legend
Tools/Show Legend.. menu option displays a plot legend window (see Figure 6). In addition to the color legend, it also shows the energies or fluxes corresponding to the channels. The plot legend window does not disable any other controls or menu buttons, it can be left on the screen or dismissed using the Done button. If the window is left on the screen, the legend text will change if a file of a different type (e.g., a file containing (-particle instead of proton data) is loaded.
Data Values
Tools/Show Values.. menu option displays a data values window. It is useful for examining exact values of the data points on a plot. If the left mouse button is clicked while the cursor is anywhere in the plot area, the data values window is updated to contain the values of all data components at the time corresponding to the coordinates of the cursor.
[pic]
Figure 7. Annotation Window.
Annotate Plot
The data displayed in the plot window can be annotated, and the resulting annotations can be printed, using the Annotate Plot.. option under the Tools menu (see Figure 7).
The annotation tool has three modes, Draw, Edit, and Select. Draw mode is default and is used to place an annotation object on the plot window. Edit mode is used to change the appearance of an annotation object on the screen. Select mode is used to select an already drawn annotation object for further editing.
To place an object on the plot window switch to Draw mode, select the object type by pressing Text, Lines, Polygons, Circles, or Squares button and then click the left mouse button on the desired spot in the plot window. An object of the selected type will be drawn in the window, and the annotation tool will automatically switch to Edit mode.
While in Edit mode, the current annotation object has square “handles” that can be dragged with the left mouse button to change the size, position, or orientation of the object. Controls in the lower part of the annotation window can also be used to modify the attributes of the current object, such as line style, fill style, font type and alignment. To complete editing of an object it needs to be “closed”. “Closing” an object is accomplished by pressing the right mouse button anywhere in the plot window. After an object is closed, the annotation tool will automatically switch to Draw mode.
Select mode is used to resume editing of objects that have previously been “closed”. To select an object, switch to Select mode and click the left mouse button on an object. The selected object will flash a couple of times and the annotation tool will switch to Edit mode. To delete an object, select it and then change the object type (e.g. to delete a line of text, select it and press Lines button).
Refresh and Clear buttons in the top row of the annotation window can be used to (respectively) redraw and delete all annotation objects currently displayed. Pressing the Help button will display an on-line help for the annotation tool. Finally, pressing Done button will dismiss the annotation window.
The annotation window must be displayed on the screen in order to print a hardcopy of the annotations along with the data plot. Also, the Data Values window will not function when the annotation tool is running because they both use the left mouse button.
[pic]
Figure 8. Printer Setup Window.
Printer Setup
Tools/Printer Setup.. menu option displays the Setup Printer dialog (see Figure 8). It allows the user to configure various printing options without printing a plot. The same task can be accomplished by selecting Print from the main menu, except a hardcopy will actually be produced. If you press Cancel at any point, configuration changes will not be saved.
Select Printer Type push-buttons toggle between PostScript and PCL (LaserJet-compatible) output. Only monochrome PCL output is supported, so PostScript is preferred for best results (even on black-and-white printers different traces will appear in different shades of gray).
Check the Include Legend box to produce a legend to the right of the plot. This option is particularly useful when printing to black-and-white printers.
Under Unix, Print Command field contains the shell command used to send a file to a printer (e.g.
lpr -Pps). Do not include the filename in the command line, Archive Browser will append it automatically. Under Microsoft Windows, the Print Command field contains the words “Current Windows Printer”. This means that the Archive Browser will send its output to the printer designated as default in Print Manager. On any platform, if the Print Command field is left blank, only a PostScript (idl.ps) or PCL (idl.pcl) file will be created in the temporary directory (/tmp on Unix, directory pointed to by the TMP environment variable on Microsoft Windows, and in the current folder on Macintosh). The resulting file can be sent to a printer by any acceptable method.
Setup Command field contains an IDL command that is to be executed on the current print device (PS or PCL) immediately before the output is drawn. It does not need to be changed under normal circumstances. Change it only if your printer requires special setup to print IDL output. For example, to print on legal paper, change the command to device, xsize=12.5, /inches.
Save Image
Tools/Save Image.. menu option allows the user to save the contents of the plot window to an image file. Currently TIFF (Tagged Image File Format), GIF (Graphics Interchange Format), Macintosh PICT, SRF (Sun Rasterfile), and EPS (Encapsulated PostScript) formats are supported. Encapsulated PostScript format is best for producing publication-quality plots, while the other formats can be decoded with ease by various image-processing programs.
To save the contents of the plot window, select the desired file type, type in the name of the file to be created (or select it by pressing the Browse button), and click OK.
System-Specific Notes
Unix
IDL may not work properly on some 24-bit displays with the default visual set to DirectColor. In this case all plot traces in the Archive Browser window may only appear when the mouse pointer is in the plot window, or may not appear at all. If this is the case with your display, exit IDL and enter DEVICE, PSEUDO=8 as the first command in the IDL session. This will make IDL use the PseudoColor visual and will alleviate the problem.
If the directory for saving an image of the plot was selected using the Browse.. button in the Save Image window, the file will be saved in the current working directory instead of the directory selected in the browsing window. This appears to be a bug in the Unix version of the IDL file selection routine. To save an image in the directory other than the current working one, type in the full path in the Save Image window.
Microsoft Windows
Buttons and other interface elements may not appear “grayed-out” when they are disabled. This is a limitation of the current version of IDL for Windows.
On some 24-bit displays, all plot traces may appear red or jumbled. Pressing the Plot button or restarting IDL usually solves this problem. This appears to be a bug in the current version of IDL.
If you are attempting to print to the local printer but Archive Browser does not produce a printout, make sure that the Print Manager is enabled. Start Control Panel from the Program Manager, select Printers icon and make sure that the Use Print Manager box is checked. Also make sure you have a TMP environment variable set in your AUTOEXEC.BAT file that points to a directory with at least 1 MB of free space.
Macintosh
IDL 3.5.1 for Macintosh is the first release of IDL for this platform and it does not appear to be stable enough for production-level environments. In our tests IDL crashed for no reason even on a Macintosh with 80 Megabytes of RAM. We were able to determine that Archive Browser will run reasonably reliably if the Preferred Memory Size allocated to IDL is 16 MB or more.
Even with Preferred Memory Size set to 16 MB, displaying the Data Values window crashed IDL every time. We believe that this crash is due to the instability of the current release of IDL and it will be corrected by Research Systems in the next version.
Troubleshooting
If Archive Browser displays an error message and exits to the IDL prompt while still displaying its main window, the problem can be corrected by executing RETALL & XMANAGER at the IDL prompt
If Archive Browser was not installed in the IDL LIB subdirectory it may complain about not finding the satellite position file. To solve this problem either select the file SATPOS.TXT from the directory where Archive Browser was installed (you will have to do this every time Archive Browser starts up), or make sure the Archive Browser directory is added to the IDL search path.
Every effort has been made to make sure that the program is as bug-free as possible. If you find any bugs or undesirable “features”, or would like to give us your feedback, please contact us at the address on the title page.
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