"geoGLOBE" is a world distance and time zone calculator. You enter the latitude, longitude and time zone of a location...and "geoGLOBE" tells you how far that location is from wherever you have set your "home" location, the time difference between the two locations and the actual time in both locations. In addition, a flashing dot on the map indicates the approximate location.
Some Terms
"home city" is the location you choose to calculate all other data from. When you first run "geoGLOBE", the home city will be Hughson, my home town.
"current city" is the city currently displayed in the information box at the bottom of the screen.
A "city", of course, can be any location.
"global cities" is the data file which can data on up to 195 locations.
How You Make It Go
Double click the "geoGLOBE" or "global cities" icon. Don't load this from "geoWIZARD".
Then This Happens
"geoGLOBE" runs and automatically loads "global cities".
The "geoGLOBE" screen appears. There is a two entry menu, a map of the world, and an information box which displays the data for the first city in the file. The home city is always the first city in the file.
GEOS menu
Credits
allows you to see the names of those who are responsible (even though they dodn't know it) for this.
lets you QUIT. Quitting automatically saves the "global cities" file.
CITY menu
Add City
allows you to add new locations. There is a limit of about 195 cities.
Erase City
erases the currently displayed city. If you accidentally erase a city, go to Find City (see below) and substitute "***" for the first three letters of the city. But do this right away. New cities are placed where old cities were.
Set Home
makes the currently displayed city become the new home city. All distances and time differences are now calculated from this city.
Find City
finds a city. (Duh!) You must have everything right. "Washington", for example, will not find the entry "Washington, D.C.".
Each of these entries, except Credits, has a keyboard entry.
Q=Quit
A=Add City
E=Erase City
[home]=Set Home
F=Find City.
More About Add City
When you select this, you will be asked to enter several pieces of data.
1) The location name up to 20 characters. No rules here except you can enter a name starti
More About Add City
When you select this, you will be asked to enter several pieces of data.
1) The
location name
up to 20 characters. No rules here except you can enter a name starting with a "*". Who the heck would?!!
2) The
latitude
of the location in degrees and minutes. It must have the following format:
dd:mmD
where dd=degrees from 0 to 89
mm=minutes from 0 to 59
D = N(n) or S(s)
3) The
longitude
of your location in the following format:
ddd:mm:D
where ddd=degrees from 0 to 179
mm=minutes from 0 to 59
D= E(e) or W(w)
(NOTE: For latitude and longitude you may delete any leading zeros.)
Time Zone
relative to GMT (Greenwich Mean Time). Use the following format:
Shh:mm
where S= + or - ; + is East of GMT, - is West
hh=hours between 0 and 12
mm=minutes--must be 00, 15, 30, 45
If yo make an error in 2, 3, or 4 above, you will see a general error warning DB. Click OK and re-enter data.
ld re-enter data.
Set Home
F=Find City.
The "geoGLOBE" screen appears. There is a two entry menu, a map of the world, and an information box which displays the data for the first city in the file. The home city is always the first c
The Information Box
The four pieces of data you just entered appear along with several calculated pieces of information:
is the distance in statute miles between the home city and the currently displayed city. This is by great circle route calculations, an "as-the-crow-flies" measurement.
is the time difference based on your time zone entry. A "+" difference means you would ADD the difference to the home city's time. A "-" means you would subtract the difference.
is the computer's clock.
. is the time in the city you are currently viewing.
You can change data in the information box by clicking on the CITY, LAT, LON and ZONE.
Clicking on the globe icon will display the next city. This is circular only in one direction. The home city follows the last city.
You can also use the following keyboard entries:
C=CITY
[crsr dn]=LAT
[crsr right]=LON
G=Next City (G for Globe)
Z=ZONE
Changing LAT or LON will update DIST. Changing ZONE will update DIFF and CURRENT.
The MAP
A flashing box on the map will indicate the approximate location of the currently displayed city. If the location you are displaying isn't on the map, there will be no flash.
That's about it...
But read on if you want some more technical information.
More Stuff (Some Technical; Some Not)
1) The map is not proportionally correct. The position of the flashing box is calculated by use of look-up tables. I have tried to make the locations as accurate as possible, but don't base a major homework assignemt on them!
2) You can't access any desk accessories because I hope that this will someday
a DA of its own.
3) The reason you can't enter time zones with minutes other than 00,15,30 and 45 is that time zones and differences are looked up on a table of times ranging from +12:00 to -11:45.
4) Time zones are stored in the data file both as the actual data entry (+01:00) and as a number from the time look-up table mentioned above.
5) Differences are only stored by their look-up table number. This way, when the home city changes or the time zone changes, the only data in each city record that has to be changed is that number.
6) Latitude and longitude are stored in the data file broken down into strings. For example, a city with 37:36n and 120:52w would be stored as:
"+37","+36","-120","-52"
This makes computation of the distances much easier.
7) After Add City, Find City, clicking the globe, or changing LAT or LON, you will see a rapid flickering of the cursor. What you are seeing is the switching back and forth from the GEOS kernal and the C64 kernal. This is, of course, the floating point math routines at work, calculating the distances. This method of accessing the C64 routines was developed by Robert Knop, who graciously uploaded them for all of us to use.
8) The great circle distance calculation routine is a fairly common formula which I downloaded in basic and converted to ml and then to GEOS. There are two test locations for the basic program which I have used to test mine. They work. So do my short distance tests. This program may not be perfect, but it's pretty damn close.
If you want to test for yourself, find either "Yacht (Test 1)" or "Cornwall (Test 2)". Make either one of these the "home" location, then go to the other one. The distance should read 3671.
9) The file included with this has about thirty locations on it. Most of the time zones are right, but I had to guess on a few. I don't have a really good time zone map.
Dave Ferguson
DiBieF
geoGLOBE
David B. Ferguson
Copyright 1990
"geoGLOBE" is a world distance and time zone calculator. You enter the latitude, longitude and time zone of a loc
(.txt)