Muslim Qibla Compass
WH_Qibla AddIn
By Waleed Hasan
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IntroductionL:
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This REX AddIn calculates the direction of Muslim Qibla
(direction to Makkah)
Installation:
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-Upload WHqibla.rex (the AddIn) & CityTable.rex (memo file)
-Edit the CityTable memo for your home city (see below)
Usage:
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The REX has a city table used in the World clock but
it contains only degrees - no minutes - so I had to
use a separate memo file for that.
*The city table format:
-CityName,LongDeg,LongMin,LatDeg,LatMin,GMT,DTS,HeightAboveSeaLevel
-East & South are negatives
-Home city is preceded with an '@'
*Example:
City : Alexandria (Egypt)
Longitude : 29:55 East
Latitude : 31:13 North
GMT : +2
DayTimeSaving : No
Height above sea-level : 0
The line in the city table would be like this:
Alexandris,-29,-55,31,13,2,0,0
*Changing the home city:
The program will scan the city table for a line precededed with '@'
To do that I simply open the CityTable memo file & modify it.
I mark the '@' & using EDIT->CUT then move to the new city then
EDIT->PASTE and save the file.
I wanted to have an easier way to select the home city but no room
to do anything!
Error codes:
------------
-Err:301 : DB error, no memos??? => ???
-Err:401 : DB error,Can't open Line DB!? => ???
-Err:501 : Can't open City Table. => Upload the citytable.rex
-Err:502 : No home city found. => Mark a city with '@'
Bugs - They are every where!
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I've tried my best to make this program correct.
The error is about 1 minuite (+ or -) which is quite acceptable.
Please send any comments to me wh_hsn at hotmail dot com.
Some weird things sometimes happen while compilation:
-Compiling the same program sometimes gives bad code - just
re-compile (no need to change any lines!) & it'll work!
This is a bug in the linker I think!
Many times I compiled & upload the code & got error "501"
{can't open city table} all I do is to re-compile the same
code and upload it again & the addin runs perfectly!?!?
-Also sometimes the compilar asked me for missing ORG! -
just & re-compile & it'll work!
History:
--------
23Nov2001 : The idea.
24Nov2001 : Using transdental funcions from the web.
06Dec2001 : Finally got everything working including memo
routines from cMemo by Chris Harris.
30Jan2002 : I corrected the original math routines in sccZ80
& used them instead of my own math implementations.
That reduced code size & I managed to draw the
compass & the Kaaba icon :)
12Feb2002 : Published to the REX community.
ToDo:
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-If we can put the memo routines in a separate library addin
we can handle the city table more easily.
Acknowledgment:
---------------
-Goes to everyone in the REX developers group, specialy Myles,
Chris Haris (for the Memo handling routines), Dom & Dan for the
great compilar & library.
Referecnces:
------------
-The equation to calculate the Qibla is deducted from the paper:
"The Correct Qibla" by S. Kamal Abdali, (Last Revised 1997/9/17)
(
geocities.com/wh_hsn)