Busa I asked Matt that very question some time ago, and he told me it's 'as the crow flies', like Raptor said.
I thought distance wouldn't be too much of a bother when most of the members have their own transport? I have noticed that a lot of men put their name down to attend events that are close to their county. They don't seem to venture much further.
yes i'd worked that out - re the helicopter bit - but its no good to us. liverpool is supposed to be 30 miles from blackpool but it takes over an hour to get there, by motorway. (by car anyway). i hav'nt been convinced. surely it could be changed. bet there's a few peed off about that. and thats the only fault i can find with bm. not bad eh.
have to agree with 'busa.. a quick jaunt from Swansea down the M4, say 40 miles, is not the same a trek to Somerset/Devon but they show in the same search results.. Bit like fleaBay distances.
viaMichelin's good for route options & accuracy, but not really an answer for filtering searches.
the only prob with any accurate distance finder,
is it would have to have both post codes to calculate the real distance,
not just a gereral "town" area, and not sure most folk would be happy with just anybody having access to their post code?
also it would need to do an acurate calculation for every member against every other member to feature in normal search results, and this is a big number!
personally cant see any probs with the distances as it is only a rough guide and if you are looking at the profiles the first part of their post code is there so you can figure it out yerself if it bothers ya that much
ah @ stroggy,
surely there is no prob with the distances,
it`s just all those addy up`s and converting miles to km,
and shortest route, vs motorway distances, keeps us from actually
doing stuff in the real world rather than answering random questions
which we have no control over or interest in other than
free wheeling out brains till daylight again?
As has been said, the distances are a guide. Deciding if you're actually going to go somewhere just involves engaging your brain. Sometimes a technical solution isn't always the best, just run off to Google maps for a more accurate result.
Distances use the first part of your postcode only. This is for security reasons AND performance reasons. Some postcode areas cover 5 miles, some cover a much larger area - there's nothing I can do about that.
Regarding the calculation method... each postcode in the database has a latitude and longitude coordinate. There's a very complex mathmatical script which calculates the direct distance along the earth's surface between 2 sets of coordinates.
Now, each time you run a search the server goes through 3,000 postcode areas and works out the distance to each. That's 3,000 complex mathmatical calculations. Once it has a list of postcodes that are within your selected radius it runs another search on the database "show all profiles/events with these given postcodes".
Now... do you know how long it takes your GPS to work out the route for a long journey? Imagine asking your GPS to do that 3,000 times BEFORE you could set off?! Well that's what you'd be asking the server to do... calculate thousands of routes before it gives you the results.
Not only that... but I have no way of calculating routes. There's no way the web server can do that. I'm not the RAC/AA, the server doesn't have some special GPS system attached to it that can do such a task.
So the answer is... if you wanted routes to be calculated, we'd have to invest probably millions of pounds in a sophisticated system capable of calculating routes, and.... you'd have to wait about an hour for your search results!
As it is now you get your results in less than 1 second and with enough accuracy for you to decide whether to take up further contact.
oh that's not techy lol... if i had to really explain how the system works it would boggle your mind. The distance calculation script alone (just the bit that calculates from one postcode to one other) took me nearly a month to write. I had to research loads of university documents for the mathmatical equation and then convert it into computer programming. My script was so cool that my college teacher at the time asked me to write an essay/assignment about it!