            WXtrack - Satellite and ground picture prediction

Purpose:

This program is designed to predict the tracks of weather satellites both as 
paths above the earth, and as images produced by these satellites when 
scanning the ground.  It was designed for use during the early stages of my 
satellite receiving activities, when clouds and interference prevented easy 
identification of what I was actually observing!

It can read processed satellite images from one or more folders of your 
choice, and present these images side-by-side with the ground track 
prediction.  To make visual correlation easier, minute markers are produced 
on the predicted image to match those on NOAA APT transmissions.  Map 
overlay images suitable for subsequent combining with actual satellite 
pictures can be produced.


Known Limitations:

 o  I do not have full scanner parameters for the RESURS and METEOR 
 satellites, so ground tracks are based on my best estimates comparing with 
 actual received pictures.  It seems that RESURS may not scan quite 
 symmetrically with a south-bound image being centred a little further west
 than the predicted ground path.

 o  The program displays most dates and times in UTC


Installation, Files & Running:

Extract all files from the Zip file to a location of you choice, and run
WXtrack.exe.  The files included in the archive are:

  WXtrack.exe		the main program
  WXtrack.hlp		the help file
  WXtrack.cnt		the help contents
  SmallUserMap.jpg	900 x 450 pixel world map
  LargeUserMap.jpg	1800 x 900 pixel world map
  ReadMe.txt		this file!
  resource.2li		some 2-line orbit information files
  stations.2li			"
  weather.2li			"

  etopo5.elev           5 minute elevation data (not supplied)
  countries.dat         country and state boundary data (optional download)
  Overlay.bmp           master overlay bitmap (optional download)

Note that if you use an old version of PKUnZip, the long filenames will not 
be extracted correctly and will require renaming to the names above for 
correct program operation.

If you wish a Spanish language help file, please see Ferran Alegret's Web 
site at: http://www.qsl.net/ea3dlv.  I am very grateful to Ferran for making
this available as his time permits.

You should update the element files regularly, perhaps once a fortnight, 
from the Web site: http://www.celestrak.com/NORAD/elements/ and get the 
files: resource.txt, stations.txt and weather.txt.  Rename these as *.2li or 
*.tle when you have downloaded them.  I use a separate name both to indentify 
the files in Explorer and to avoid the program crashing when trying to read 
its own "ReadMe.txt" as orbital data.  Dr T S Kelso has articles at 
http://celestrak.com/columns/V04n03/ describing the format of the data.


You may need three other files:

1 - If you don't already have Borland's run-time library, you will also need 
to download the file VCL40.zip from any site offering it.  For example:
  http://www.davidtaylor.freeserve.co.uk/software/runtime.html  (601KB)

Extract the file VCL40.BPL and copy it to your Windows System folder (e.g. 
\Windows\System or \WinNT\System32).  Do not overwrite newer versions.

2 - If you don't already have the PNG LPng.dll library, you will also need to 
download the file lpng.zip from any site offering it.  For example:
  http://www.davidtaylor.freeserve.co.uk/software/runtime.html  (93KB)

Extract the file LPng.dll and copy to your Windows System folder (e.g. 
\Windows\System or \WinNT\System32).  Do not overwrite newer versions.

3 - If you do not have a recent Microsoft product installed, such as Internet
Explorer, it is possible that you may get an error message saying that "This 
control requires version 4.70 or greater of COMCTL32.DLL".  In this case, 
you will need Microsoft's Common Control Library update from: 
  http://www.microsoft.com/msdownload/ieplatform/ie/comctrl.asp  (400KB)


Optional files:

If you wish to generate map overlays, you will need the file countries.dat
which is available on the Web at this address:
  http://www.davidtaylor.freeserve.co.uk/software/countries.zip (452KB)

Extract the file countries.dat to the same folder as WXtrack.exe.

If you wish, you can avoid having to generate the large master bitmap overlay
file (which requires at least 32MB to generate at a reasonable speed) by
downloading a pre-compiled version from:
  http://www.davidtaylor.freeserve.co.uk/software/overlaybmp.zip (404KB)


Usage notes:

The program has three tabs, Setup, World Map and Ground Path.  It starts on 
the World Map, but note that you will need to visit the setup screen when you 
first run the program, and drag and drop your choice of satellites from the 
Available to the Active list box.

On the Setup screen, you may first wish to enter the ground co-ordinates of 
your location.  You can choose the satellites that interest you by dragging 
and dropping from the available satellites list.  This list is built up from 
all text files *.2li or *.tle in the same folder as WXtrack.exe, or in a 
folder of your choice.  It is up to you to keep these files up to date.  The 
pass generator will show you a list of passes for a single day, and when you 
select one of these passes the buttons which link to the world map and ground 
path tabs become enabled.  If no files with satellite details are found, the 
list of available satellites will be blank.  You can call the files anything 
you want - the program will read all files ending in 2LI or TLE will be read
by the program.  Duplicate entries for satellites in multiple files are 
allowed, but the program will only use entries with the greatest epoch 
(i.e. the most recent data).

You should update the element files regularly, perhaps once a fortnight, from
the Web site:  http://www.celestrak.com/NORAD/elements/  and get the files:
resource.txt, stations.txt and weather.txt.  Rename these as *.2li or *.tle
when you have downloaded them.

You can print a diary of passes for the next few days, an ephemeris, either 
from the Setup tab, or from the main File, Print pass list menu.

The World Map tab allows real-time and manual updates of the chosen satellite 
positions, or you can open a file from WXSAT (e.g. 12250000.bmp for December 
25th) to make the program use the date and time from the file as the map time.  
Note that you can only set the time to the nearest minute.  The "selected" 
satellite will have dotted markers showing its scan pattern on the ground.  
The track of the satellite is shown by five dots marking the position in the 
previous five minutes.

The Ground Path tab allows two functions, the prediction of a ground path 
given the satellite, start of pass, and direction of pass, and loading an 
image produced from WXSAT.  You can choose the folder (or folders) containing 
these images from the setup tab.  The filename is assumed to be in WXSAT 
format, but to allow the viewing or processed visible or IR images, various 
file extensions are recognised:

Visible: -2.jpg, V.jpg, V.png, V.bmp, -C.jpg, C.jpg, C.png, C.bmp, B.bmp,
         -4.jpg, I.jpg, I.png, I.bmp, .jpg, .png, .bmp

IR:      -4.jpg, I.jpg, I.png, I.bmp, -C.jpg, C.jpg, C.png, C.bmp, B.bmp,
         -2.jpg, V.jpg, V.png, V.bmp, .jpg, .png, .bmp

So if today is March 26, and the time 12:58 UTC, then the filename from WXSAT 
might be 03261258.bmp, and you may have processed the pass to produce a 
visible channel file that you have called 03261258-2.jpg.  This file would be 
the first one found as shown in the tabel above.  The program also tries to 
look for files a few minutes on either side on the nominal.

I have specifically included PNG file support as this format is typically 
only about 2/3 of the size of a BMP file, but without any loss of quality that 
is associated with JPEG files.  Storing images as JPG files can cause errors 
in the level of the telemetry bars, required for apparent temperature 
measurement.

(Note that I am assuming that an image contains a single picture, not a 
combined side-by-side channel A and channel B picture.  I currently store 
side-by-side PNG images as my master image, and processed JPG images for each 
channel.)

You can zoom and scroll both the map and the picture.  Normally, scrolling 
the map will scroll the picture as well, but as there might be some 
misalignment, perhaps the satellite wasn't acquired at the start of the pass,
scrolling the picture will, intentionally, not scroll the map.

As ground path prediction can take some time, pressing the escape key will 
interrupt.  Each time a new ground path map is generated, a copy will be saved 
as a file named Result.jpg in the same folder as the program.  Note that this 
file will be overwritten every time a new pass is created.


World Map data:

The predicted picture quality on the Ground Path and Flight tabs can be 
substantially enhanced by downloading higher resolution topographic data than 
that supplied with the program in the *UserMap.jpg files.  The backdrop on the 
World Map tab will not be affected, only the Ground Path and Flight tabs.  The
highest resolution data supplied with the program is at 12 minute intervals,
and is compressed with JPG resulting in artefacts.  If the image quality is
adequate for you, then you do not need the higher resolution data.  However,
using the ETOPO5 5 minute data will increase the number of pixels in the
predicted image by about 5.6 times, more when you consider that it is not
compressed.

The program will use the US National Geophysical Data Center (NGDC) ETOPO5 5 
minute data file for ground path prediction if the file etopo5.elev is present 
in the same folder as the program executable.  This data file may be obtained 
from the Internet, for example:

  http://edcwww.cr.usgs.gov/Webglis/glisbin/guide.pl/glis/hyper/guide/etopo5
  18662400 bytes
or:
  http://www.geol.binghamton.edu/faculty/jones/etopo5.zip
  18666720 bytes

Be warned that this zip file is an 11MB download that expands to 18MB when 
unzipped.  But the results _are_ worth it.  NGDC can supply the data on CD-ROM 
(product code 1093-A27-001).  I am advised that the price is around $100 or 
online ordered $75, plus $11 shipping and handling, plus for outside the US a 
currency charge of $10.  The product number is G01093-cdr-A0001 and the e-mail 
address is pkd@ngdc.noaa.gov, the URL is http://www.ngdc.gov/mgg/fliers/93mgg01.html

I have now discovered that data from these two sources are not identical, the 
earlier Jones data has one extra 16-bit field per line, and has a different 
byte order.  WXtrack attempts to determine which file you are using, and to 
behave appropriately.  Using the high-resolution data file will not alter the 
appearance of the world map display, simply the predicted ground path.


Using Image files:

The images must be named according to the WXsat convention - MMDDhhmm.bmp or 
whatever.  For example, without a pass selected, the program starts up with 
the date 26th February 1999 at 1327 in the "When" box on the "Ground Path" 
tab.  It would therefore look for files named 02261327.jpg.  When using the 
"Timeframe from File" option on the World Map page, loading a file merely sets 
the date and time for the satellite display.


Notes:

The program is written for Borland's Delphi 4.03, but you do not need access 
to Delphi to run WXtrack.  The program has been developed on Windows NT 4.0 
and runs on Windows 2000, 95, 98 as well.


Release information:

2000 Feb 21  2.2.8  Display actual, not generated, direction on overlay text
                    Spanish language help file is available

(Earlier update information is contained in the program's Help file.)


Program Status & Distribution:

This program is freeware, and remains copyright of David J Taylor, Edinburgh, 
2000.  This program is provided "as is", without any support.  Whilst I cannot 
answer queries relating to the use of this program, I'd value any comments or 
suggestions for improvements you may have.  If you report a problem, be sure 
to include the program version number (from the Help, About command), and the
details of the operating system you are using.


Acknowledgements:

First, I would like to thank all the folk who have bothered to download and
try out this software, and the valuable suggestions you have all made are
built into the current version of the program.

Many routines were modified from Dr TS Kelso's invaluable SGP4 routines, used 
with permission, which are:
  Copyright (c)  1991-1999, Dr TS Kelso, All Rights Reserved
  E-mail:   tskelso@celestrak.com
  Web site: http://celestrak.com

Dr TS Kelso's site at: http://www.celestrak.com/NORAD/elements/ provided the
orbital elements, and is your source for up to the minute data.

Footprint calculation code adapted from James Miller's (G3RUH) 
"PLAN-13 SATELLITE POSITION CALCULATION PROGRAM" available at:
  ftp.amsat.org  /amsat/articles/g3ruh/a111.zip

The PNG support is from Edmund H Hand's interface to LPng.dll
  E-mail:  edhand@worldnet.att.net

The library LPng.dll is freeware I believe, but the source is:
  Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
  Copyright (c) 1996, 1997 Andreas Dilger
  Copyright (c) 1998 Glenn Randers-Pehrson

TVersionInfoResource is from Brad Stowers
  http://www.pobox.com/~bstowers/delphi/
  Copyright bstowers@pobox.com (CompuServe 72733,3374)


Contacting the author:

Web site:  http://www.davidtaylor.freeserve.co.uk
E-mail:    davidtaylor@writeme.com
2000 February 21
