Real Navigation Mod files - FINAL

[Ad Günther Lütjens]

+1
all Link invalid.
Please.

[don1reed]

Using the Python/Stellarium method for Celestial Navigation with SH3 & SH4.

The Script is in your [here is example of what mine looks like]

My Documents/SH3/data/cfg/Careers/(skippers name)/1/(skippers name).map

Every time you save a game, SH3/SH4 updates this file to your PRECISE location on the F5 Chart.

Here is what my Python script file looks like, note what I've highlighted in RED below. I happen to play multi-games and this is the game I play on fridays:

+++++++++++++++++++++++++++++++++++++++++++++++

# By Michael Jones, 01/01/2008. mjones004@ameritech.net
# Revised 11/29/2009 to work with Stellarium 0.10.2
# This program reads the latitude and longitude data for a
# sub in Silent Hunter III, IV and creates a startup script for
# Stellarium. This sets the Date, Time and Location of the
# sub in Stellarium, allowing players to use celestial navigation in the game.

import string, os, sys

####### Edit Locations here ############

# Change the directory on the next line to point to SaveData.map in your saved game directory.
savedgame = "C:\\Users\\Gamer\\My Documents\\JAG\\data\\cfg\\Careers\\z\\0\\Fri.map"
# Set the Stellarium directory
stellocation = "C:\\Stellarium"

####### End Editable locations #########

# read savegame.
f=open(savedgame,'r')
content= f.read()
f.close()
# find lat & Lon in the file
start = content.find("Waypoint")
longst = content.find("Pt0=",start)
longnd = content.find(",",longst)
latnd = content.find(",",longnd+1)
# convert to dec deg
longitude = float(content[longst+4:longnd])/120000
latitude = float(content[longnd+1:latnd])/120000

# get date&time (input)
date = raw_input('GMT yyyy/mm/dd :')
time = raw_input('GMT hh:mm :')

# set the ocean label
if (-90 < longitude <= 30):
ocean = "Atlantic Ocean"
elif (30 < longitude <= 105):
ocean = "Indian Ocean"
elif (longitude <= -90 or longitude > 105):
ocean = "Pacific Ocean"

# Write startup script.
date = date.replace('/', ':')
longitude = str(longitude)
latitude = str(latitude)

stella=open(stellocation + "\\scripts\\JAG.ssc",'w')
stella.write("core.setDate(\""+date+"T"+time+":00\ ")\n")
stella.write("core.setObserverLocation("+longitude +", "+latitude+", 2, 0, \"SH3 Navigation Point, "+ ocean +"\", \"earth\")");
stella.close()

# now open stellarium and take your star sights
prog = "start /d \""+ stellocation +"\" stellarium.exe --startup-script sh3.ssc"
os.system(prog)
sys.exit()
++++++++++++++++++++++++++++++++++++++++++++++++

Inside this scrip file is the formula the game uses for determining your geo coord when it updates your *.map file.

Real Navigators plot their positions five times per day (There's something religious about that. ;-) )

Body: Sun and sometimes Sun and/or Moon, used for Running Fixes.
Daylight sights:
1. Ante Meridian (A.M.)
2. Meridian (Noon)
3. Post Meridan (P.M.)

Body: Stars, Moon, & Planets, used for Fixes.
4. Evening Twilight sights. (Round of three bodies)
5. Morning Twilight sights. (Round of three bodies)

Inside my *.map file: (Located at the bottom of the file)

[Waypoint]
Pt8=44333.77,6863332.00,0.00

If I divide 44333.77 by 120000, I get = 0.369448, changing into degrees and minutes = 0° 22.2 E. Why East, you ask, well because it's a positive number (N and E are positive numbers)continuing
6863332.00/120000 = 57.194433 = 57° 11.6N.

The Python script file, when working properly, allows the player to input Game date and Time (GMT). It sends this data to Stellarium and allows the player to select the celestial bodies necessary to obtain a fix.

Stellarium provides the player with body's Azimuth and Altitude of the sight to the precise second of time. If a round of stars is to be obtained, one must allow seconds to ellapse between each sight to reenact what the real navigator does. Real life doesn't have a pause button.

Getting Python and Stellarium to work hand in hand is a tedious business, admittedly, and for those interested in TC other than TCx1, Celestial Navigation in SH3 is not recommended.
Then there is the issue with newer versions of Python don't get me started on that. (I once had grey hair, now I have none.)

edit:

Both Python and Stellarium are stand-alone programs and as such, it requires the player to save his game, then open python, input the date/time, which then opens Stellarium, then player must obtain the data for his virtual sights, go to Almanac for war years, then reduce the sights via either
Nories,
HO-211,
HO-229,
HO-249,
Concise Sight Reduction Tables,
or
pure math:
sin Hc = sin Lat sin dec + cos Lat cos dec cos LHA
cos Z = sin dec - sin Lat sin Hc / cos Lat cos Hc

You'll soon find you have no time left to enjoy playing the game; but, if you're determined...
Remember...Real Celestial Navigation is like doing your own Taxes five times per day. LoL

Cheers

[CaliEs]

Originally Posted by Ad Günther Lütjens

+1
all Link invalid.
Please.

http://files.mail.ru/9MBEOS (49MB)

[CaliEs]

Originally Posted by don1reed

Using the Python/Stellarium method for Celestial Navigation with SH3

Awesome. Very valueable information.

In the known nautical almancs from 1939-1945 the polaris star tables ( )are missing, which are unique for every year. Do you have those Polar star tables for the time 1939 ff. ?

[don1reed]

There is a free almanac, here:

http://www.tecepe.com.br/scripts/AlmanacPagesISAPI.isa


just type in the date you're interested in, i.e., 1/11/1939 for example.

[Ad Günther Lütjens]

Bigs thanks CaliEs

[CaliEs]

Real navigation depends on exact time measurement. But i see no clock with a hand for seconds. Only the stopwatch exists but to top it all, the stopwatch goes wrong: the stopwatch-minute is faster than the u-boat-clock-minute.
In all sh3-threads (topic search) i have not found a single demand/question about the lack of a seconds-display. I am shocked right now.

Even for dead-reckoning its essentual to know when i have stopped my engines: at 15:00:00 or at 15:00:55. At a speed of 17kts it makes a difference of 1/2 km.

[vanjast]

In all sh3-threads (topic search) i have not found a single demand/question about the lack of a seconds-display. I am shocked right now.
Even for dead-reckoning its essentual to know when i have stopped my engines: at 15:00:00 or at 15:00:55. At a speed of 17kts it makes a difference of 1/2 km.

The mod was never going to be that accurate .... for many reasons beyond our control. It was just an educational idea to make it more difficult to play

Oh.. hi all, I've just risen from the depths..

[CaliEs]

Originally Posted by vanjast

The mod was never going to be that accurate .... for many reasons beyond our control. It was just an educational idea to make it more difficult to play

What the hell are you talking about? I just was shocked about the fact that no one in those 20000 SH-3 threads has asked about the lack of a seconds-display.

I was not talking about the idea someone is really so dumb to believe that the SH3-sky is so accurat designed/modelled to get from there a position fix. Because celestial navigation depends on exact time (seconds) and a precision of one hundredth(!) of a degree. The way to fix your position with stars is - as it described by donreed here at 01-11-2012 07:35 AM - to combine SH3 with the stellarium-software.

[vanjast]

Well, you being shocked why the seconds indicator was not mentioned, and implying that not having this indicator would put you out by 500m or more, with regard to navigation. Maybe the forum doesn't think that this is important.

Linking SH3 skies/time/position to stellarium implies that SH3 must be 'accurate' enough as one has to use these as references for stellarium.

[don1reed]

@CaliEs

Stellarium provides the seconds necessary to reduce the sight to a fix.

Another stand-alone program that's been around since the days of AOTD is MQK.

It allows you to input a four digit Kriegsmarine grid and transforms it into geo coord. I use it to give me an Assumed Position for my sight reductions.

I only use the celestial canopy in SH3 to determine whether celestial bodies are visible or not. It determines if an actual sight can be taken.

The other thing that is wrong about SH3 is SUNRISE and SUNSET.

Rise occurs when the upper limb breaks surface, NOT when it's half above the horizon; and likewise, Set occurs when the upper limb dips below the horizon.

Cheers

[vanjast]

Originally Posted by don1reed

@CaliEs
Rise occurs when the upper limb breaks surface, NOT when it's half above the horizon; and likewise, Set occurs when the upper limb dips below the horizon.
Cheers

This problem is more noticable at the higher lattitudes, where the sun takes for ever to get halfway. I vaguely remember using the time that the interior light switches from red to normal, and visa versa, as an indication of sunrise/set - this seemed to be more accurate.

I just need to fire up SH3 again..

[don1reed]

I know what you mean, Van. Since the DRM was removed from SHV, I've been investigating those waters.

Cheers

[JeromeHeretic]

Originally Posted by CaliEs

Even for dead-reckoning its essentual to know when i have stopped my engines: at 15:00:00 or at 15:00:55. At a speed of 17kts it makes a difference of 1/2 km.

And why it is so important for you, when from sextant you are able to read data +-50km on clear water?
In coastal waters you navigate via a lighthouses, when you are in the middle of ocean 100km is nothink important. When you search for reported contact, you must have at first a lot of luck, because report of contact is with error about 50km, you know your position with error about 50 km, convoy is runing in some random zig-zag course, visibility is about 25km... like this it in WWII was. When you want to simulate this, you must have on mind, that realy is not a problem in the dark night break your ship by hiting a land, when you are near of coast, or near some island. Enjoy hard living of real WWII seaman :-)

Imagine, that your board clock make an error about +-5 seconds per day and value of this error depends on weather, temperature and a lot of other things.
For example depth in which your boat is. As you go down, pressure inside of boat is much higher as atmosferical and clock go slower. Mechanical watch in summer go slower as in winter (quartz watch go quicker when hot).

As long as you are out of port, the error of your board clock is bigger.
You can set up your clock only when you exactly know, where you are - so, for example when you drive over atlantic and see some coastal lighthouse in USA and you are sure which one it is. That's a moment, when you can correct your time, because you know local noon and you know your longitude. And when you do it, you don't know if you measure better time as is error of your clock :-) Realy, it was not easy to be a seaman. :-)

[Janus]

Is this mod still hosted somewhere?