| ??? 01/16/08 14:33 Read: times |
#149561 - Not entirely true Responding to: ???'s previous message |
Russ Cooper said:
On the other hand, if you only need to find the closest object, and don't care how far you actually are from it, then you don't have to worry about any of that. Just pretend that a degree of latitude is the same as a degree of longitude and calculate the "distances" in terms of degrees. This could be a problem as you get away from the equator. As you said, degrees of longitude decrease in distance as you move away from the equator. At the equator a the distance a degree of longitude is (~69 miles) about the same as the distance a degree of latitude is, but this is not true at a longitude of 45º. Even if the distance is short, you run into a problem of making Longitude Distance = Latitude Distance. For example, if you were around 45º of longitude and you had 2 objects, each 0 degrees and 1 minute away from your current location. Object 1 was at the same latitude and only differed in longitude while Object 2 was at the same logitude and only differed in latitude. Object 1 is actually about 0.82 miles away while Object 2 is about 1.15 miles away. If you are talking about a short distance what you can do is adjust for your longitude by multiplying it by a constant. |
