Basically Programming
2528 West Olive Avenue
Fullerton, CA 92633
16K TS/1000, 1500; $12.95
Were you ever taught while in school that an airplane flying from the United States to the Soviet Union flies over the North Pole? The principle involved is that of the Great Circle route. The concept flies in the face of common perception. It is shorter to travel what appears to be a curved path instead of a “straight line” when traversing great distances across the globe.
Navigators must regularly utilize the great circle concept wherein both the distance between two points and the direction to take can be calculated. All (?) that is needed is a good knowledge of non-Euclidean geometry and spherical coordinate systems…or a computer with the right software.
DISTACALC is the right software if “close” is good enough. The program calculates distance and direction along a great circle route from one point on the earth to another. It also estimates your present location if you know the point from which you departed and the direction and distance you traveled.
I asked Distacalc the distance and direction from Memphis to Nashville and back. Both cities are stored in the Distacalc database. The database is a list of 107 worldwide cities whose latitude and longitude are filed within the program.
The results obtained were satisfactory. The distance was given in statute and nautical miles and in kilometers. In addition, the azimuth, the direction in degrees measured clockwise from north, told me which way to travel to get from one to the other. For the return trip the direction should have been 180 degrees different. It was in error by one degree.
If the two points involved are not among those listed, then you can add them to the database. The name, latitude, and longitude must be entered. The file holds up to 200 locations. Individual cities can be deleted, or a new file can be started.
The second option calculates your new position if you know your former location (latitude and longitude) and the direction (azimuth) and distance (in nautical miles) you’ve traveled. The term for this type of calculation is “dead reckoning”. I used the same two locations and the direction and distance of travel previously calculated to determine the accuracy of this option.
The results were very close but not in perfect agreement. The calculation of my new position should have been identical to the latitude and longitude for each destination city. Instead it was off by one to two minutes. A “minute” is 1/60 of a degree. This translates into 1-2 miles of error for the 180 mile trip.
In short the distances can be considered accurate calculations, while the directions are close estimations. The instruction booklet warns that this is the case. Use Distacalc to plan your vacations but not to aim your ICBMs. (Editor’s Note: since nuclear warheads generally clear quite an area, it’s probably close enough for them, too!)
RAIDERS OF THE LOST TOMB
Ever wish you could visit Egypt with its tropical oases and trees, blowing desert sand, and ancient stone pyramids? In RAIDERS OF THE LOST TOMB, one can almost feel the burning sand sifting through your toes as one plays the game.
Your mission is to find four sacred stone tablets scattered throughout five levels of a long-forgotten Egyptian pyramid, and return safely to the first room where you entered.
Sound easy? Alas, as in most games, it is not. One must search 100 rooms (20 per level) and be on guard against bottomless pits, slithering snakes, ghoulish ghosts, and mummies that rasp in their tattered wrappings. However, one is armed with a limited number of knives which can be thrown at snakes and mummies to kill them.
Other helps on one’s travels’ through the tomb are warning messages which warn of possible impending doom up to one room away. Messages 11ke “Ghosts nearby”, “I hear snakes” “I feel a draft”, and smell a mummy” warn of danger. Ladders are found to move up and down between levels, and, if you are lucky, one might find the rare blue ruby that has the power to instantly kill any wandering wrappings one might run into.
The game is made by Timeworks, which stopped making games games for the Timex/Sinclair computers in 1983. The programs put out by this company are excellent, and try to use all of the features of a computer. Now, this same company produces programs for the Commodore 64. RAIDERS OF THE LOST TOMB 1s now available from JPR Software, P. O. Box 4155, Winter Park, FL 32793; 305/273-1126. This program is for use on 16K ZX8ls, TS1000s or unexpanded TS1500s. Cost is $6.00.