ST Alpha - "Seriously, I need someone to check my math. I bet Reagen could do it." (Reading a Post)

SlickerTalk
Search Archives
The Leaderboard
The FAQ

Down to Post

Backboards:

Posts: 151

Seriously, I need someone to check my math. I bet Reagen could do it.

Posted by loosilu at work (aka loosilu2) Sep 14 '10, 13:35

to calculate distance between two points, using latitude and longitude in decimal degrees:

=SQRT(((LAT!-LAT2)*6080*60))^2+((((LON1-LON2)*6080*60)/COS(RADIANS(LAT1+LAT2/2))))^2

Responses:

LAT! should be LAT1 ... - zork Sep 14, 13:42 15
- yeah, I just wrote it as LAT for simplicity here. It's a cell number in excel. - loosilu at work Sep 14, 13:44 14
  - Without knowing what the conversion factors are, there is no way to tell you the math is correct, imo. (nm) - musubi Sep 14, 13:45 8
    - hmmmm, what conversion factors are you referring to? -- nm - loosilu at work Sep 14, 13:48 7
      - the 6080 and 60, I'm assuming are unit conversions. (nm) - musubi Sep 14, 13:54 6
        
        the 6080 is to convert to feet. I don't know about the 60. - loosilu at work Sep 14, 13:57 5
        
        oh wait, I'm averaging to find the center point. -- nm - loosilu at work Sep 14, 13:58 4
        
        Yes, averging would find the mid-latitude, but why then cosine that? - musubi Sep 14, 14:01 3
        
        I don't know!!! *cries* I know, I know, I have asked him several times to tell me what's what. - loosilu at work Sep 14, 14:07 2
        
        Just put in a series of known points and test if it gives you an accurate reading. - musubi Sep 14, 14:09 1
        
        I am, and it's not. I know I got something wrong. that's why I'm asking. -- nm - loosilu at work Sep 14, 14:28
  - times 60 would be for "minutes" but you said the coords are decimal. -- nm - zork Sep 14, 13:45 4
    - the 60 is bothering me. -- nm - loosilu at work Sep 14, 13:49 3
      - me too plus I think you meant ... - zork Sep 14, 13:52 2
        
        I have 350 locations, and for each of those I have to find the closest among 120 shelters. It is going to be a spreadsheet with a formula. -- nm - loosilu at work Sep 14, 13:55 1
        
        so far this is the best I can find ... -- (link) - zork Sep 14, 14:07
spawn said it looks good. I'm sure he wouldn't be trying to mislead. (does it take into account the curvature of the earth?) -- nm - Beryllium Sep 14, 13:37 8
- of course, the Earth is not a sphere. It's more of an oblate. -- nm - Reagen Sep 14, 13:39 6
  - you know who else is an oblate? my brother. - loosilu at work Sep 14, 13:40 1
    - I haven't done radian math in ages. -- nm - Reagen Sep 14, 13:42
  - Your face is an oblate. -- nm - Beryllium Sep 14, 13:40 3
    - as is everyone's. -- nm - Reagen Sep 14, 13:41 2
      - if you live in a hall of mirrors. -- nm - loosilu at work Sep 14, 13:42
      - oh, of course. I just thought I'd point out yours in particular. -- nm - Beryllium Sep 14, 13:41
- um, that's what the radians are for. -- nm - loosilu at work Sep 14, 13:37

Post a message top

Seriously, I need someone to check my math. I bet Reagen could do it.

Replies are disabled on threads older than 7 days.