[SOLVED] Calculating distances ...

[budimir]

Hey guys,

 

I'm creating a script where I should display distances between two cities. User can choose From - To cities and then distance is displayed

 

For example:

 

City 1    ->    City2    = 56km

City55    ->  City72  = 110km

...

 

In my DB I have this fields:

ID

date

from_city

to_city

distance

 

How do I calculate which is distance from one city to another???

 

[genericnumber1]

Can you post, perhaps, 5 database entries and then the two cities you want the distance between to give us a working example to think off of?

[budimir]

Here it is:

 

ID  From        To        Distance

1    Zagreb    Karlovac  52Km

2    Zagreb    Knin        274Km

3    Zagreb    Virovitica 154Km

4    Zagreb    Split        374Km

5    Karlovac  Pula        234Km

 

These are values from DB.

 

I'm not sure how to calculate distance (for example) from Karlovac to Knin??? And other combinations??

[genericnumber1]

With this data it isn't possible to calculate the distance from karlovac to knin. You would need to use the angle between the triangle knin/zagreb/karlovac along with the law of cosines to find the distance... Unfortunately since you don't have the angle it's impossible to tell.

[budimir]

That's what I thought. I thought that maybe there is a way.

 

Thanks a lot for your help.

[genericnumber1]

It would also be doable if you could triangulate the position of the two points from 3 locations (eg if you had 2 locations other than zagreb that had their distances from knin and karlovac), but this would be a fairly advanced technique.